Release 0.6.15

- Make peering much faster in medium to large clusters - Fix a reenterability issue which could rarely lead to peering process hangs
Rename cli_rm -> cli_rm_data, cli_snap_rm -> cli_rm
2022-03-06 19:16:34 +03:00 · 2022-02-24 14:34:14 +03:00 · 2022-02-20 00:21:24 +03:00 · 2022-02-20 00:21:19 +03:00 · 2022-02-19 19:25:55 +03:00 · 2022-02-19 18:28:12 +03:00
67 changed files with 2378 additions and 1041 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,6 +2,6 @@ cmake_minimum_required(VERSION 2.8)

 project(vitastor)

-set(VERSION "0.6.12")
+set(VERSION "0.6.15")

 add_subdirectory(src)
--- a/README-ru.md
+++ b/README-ru.md
@@ -55,11 +55,11 @@ Vitastor на данный момент находится в статусе п

 ## Планы развития

- Поддержка удаления снапшотов (слияния слоёв)
 - Более корректные скрипты разметки дисков и автоматического запуска OSD
 - Другие инструменты администрирования
 - Плагины для OpenNebula и других облачных систем
 - iSCSI-прокси
+- Упрощённый NFS прокси
 - Более быстрое переключение при отказах
 - Фоновая проверка целостности без контрольных сумм (сверка реплик)
 - Контрольные суммы
--- a/README.md
+++ b/README.md
@@ -49,11 +49,11 @@ breaking changes in the future. However, the following is implemented:

 ## Roadmap

- Snapshot deletion (layer merge) support
 - Better OSD creation and auto-start tools
 - Other administrative tools
- Plugins for OpenNebula, Proxmox and other cloud systems
+- Plugins for OpenNebula and other cloud systems
 - iSCSI proxy
+- Simplified NFS proxy
 - Faster failover
 - Scrubbing without checksums (verification of replicas)
 - Checksums
--- a/csi/Makefile
+++ b/csi/Makefile
@@ -1,4 +1,4 @@
-VERSION ?= v0.6.12
+VERSION ?= v0.6.15

 all: build push

--- a/csi/deploy/004-csi-nodeplugin.yaml
+++ b/csi/deploy/004-csi-nodeplugin.yaml
@@ -49,7 +49,7 @@ spec:
            capabilities:
              add: ["SYS_ADMIN"]
            allowPrivilegeEscalation: true
-          image: vitalif/vitastor-csi:v0.6.12
+          image: vitalif/vitastor-csi:v0.6.15
          args:
            - "--node=$(NODE_ID)"
            - "--endpoint=$(CSI_ENDPOINT)"
--- a/csi/deploy/007-csi-provisioner.yaml
+++ b/csi/deploy/007-csi-provisioner.yaml
@@ -116,7 +116,7 @@ spec:
            privileged: true
            capabilities:
              add: ["SYS_ADMIN"]
-          image: vitalif/vitastor-csi:v0.6.12
+          image: vitalif/vitastor-csi:v0.6.15
          args:
            - "--node=$(NODE_ID)"
            - "--endpoint=$(CSI_ENDPOINT)"
--- a/csi/src/config.go
+++ b/csi/src/config.go
@@ -5,7 +5,7 @@ package vitastor

 const (
    vitastorCSIDriverName    = "csi.vitastor.io"
-    vitastorCSIDriverVersion = "0.6.12"
+    vitastorCSIDriverVersion = "0.6.15"
 )

 // Config struct fills the parameters of request or user input
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,4 +1,4 @@
-vitastor (0.6.12-1) unstable; urgency=medium
+vitastor (0.6.15-1) unstable; urgency=medium

  * RDMA support
  * Bugfixes
--- a/debian/vitastor.Dockerfile
+++ b/debian/vitastor.Dockerfile
@@ -33,8 +33,8 @@ RUN set -e -x; \
    mkdir -p /root/packages/vitastor-$REL; \
    rm -rf /root/packages/vitastor-$REL/*; \
    cd /root/packages/vitastor-$REL; \
-    cp -r /root/vitastor vitastor-0.6.12; \
-    cd vitastor-0.6.12; \
+    cp -r /root/vitastor vitastor-0.6.15; \
+    cd vitastor-0.6.15; \
    ln -s /root/fio-build/fio-*/ ./fio; \
    FIO=$(head -n1 fio/debian/changelog | perl -pe 's/^.*\((.*?)\).*$/$1/'); \
    ls /usr/include/linux/raw.h || cp ./debian/raw.h /usr/include/linux/raw.h; \
@@ -47,8 +47,8 @@ RUN set -e -x; \
    rm -rf a b; \
    echo "dep:fio=$FIO" > debian/fio_version; \
    cd /root/packages/vitastor-$REL; \
-    tar --sort=name --mtime='2020-01-01' --owner=0 --group=0 --exclude=debian -cJf vitastor_0.6.12.orig.tar.xz vitastor-0.6.12; \
-    cd vitastor-0.6.12; \
+    tar --sort=name --mtime='2020-01-01' --owner=0 --group=0 --exclude=debian -cJf vitastor_0.6.15.orig.tar.xz vitastor-0.6.15; \
+    cd vitastor-0.6.15; \
    V=$(head -n1 debian/changelog | perl -pe 's/^.*\((.*?)\).*$/$1/'); \
    DEBFULLNAME="Vitaliy Filippov <vitalif@yourcmc.ru>" dch -D $REL -v "$V""$REL" "Rebuild for $REL"; \
    DEB_BUILD_OPTIONS=nocheck dpkg-buildpackage --jobs=auto -sa; \
--- a/docs/params/common.yml
+++ b/docs/params/common.yml
@@ -0,0 +1,35 @@
+- name: config_path
+  type: string
+  default: "/etc/vitastor/vitastor.conf"
+  info: |
+    Path to the JSON configuration file. Configuration file is optional,
+    a non-existing configuration file does not prevent Vitastor from
+    running if required parameters are specified.
+  info_ru: |
+    Путь к файлу конфигурации в формате JSON. Файл конфигурации необязателен,
+    без него Vitastor тоже будет работать, если переданы необходимые параметры.
+- name: etcd_address
+  type: string or array of strings
+  type_ru: строка или массив строк
+  info: |
+    etcd connection endpoint(s). Multiple endpoints may be delimited by "," or
+    specified in a JSON array `["10.0.115.10:2379/v3","10.0.115.11:2379/v3"]`.
+    Note that https is not supported for etcd connections yet.
+  info_ru: |
+    Адрес(а) подключения к etcd. Несколько адресов могут разделяться запятой
+    или указываться в виде JSON-массива `["10.0.115.10:2379/v3","10.0.115.11:2379/v3"]`.
+- name: etcd_prefix
+  type: string
+  default: "/vitastor"
+  info: |
+    Prefix for all keys in etcd used by Vitastor. You can change prefix and, for
+    example, use a single etcd cluster for multiple Vitastor clusters.
+  info_ru: |
+    Префикс для ключей etcd, которые использует Vitastor. Вы можете задать другой
+    префикс, например, чтобы запустить несколько кластеров Vitastor с одним
+    кластером etcd.
+- name: log_level
+  type: int
+  default: 0
+  info: Log level. Raise if you want more verbose output.
+  info_ru: Уровень логгирования. Повысьте, если хотите более подробный вывод.
--- a/docs/params/layout-cluster.yml
+++ b/docs/params/layout-cluster.yml
@@ -0,0 +1,200 @@
+- name: block_size
+  type: int
+  default: 131072
+  info: |
+    Size of objects (data blocks) into which all physical and virtual drives are
+    subdivided in Vitastor. One of current main settings in Vitastor, affects
+    memory usage, write amplification and I/O load distribution effectiveness.
+
+    Recommended default block size is 128 KB for SSD and 4 MB for HDD. In fact,
+    it's possible to use 4 MB for SSD too - it will lower memory usage, but
+    may increase average WA and reduce linear performance.
+
+    OSDs with different block sizes (for example, SSD and SSD+HDD OSDs) can
+    currently coexist in one etcd instance only within separate Vitastor
+    clusters with different etcd_prefix'es.
+
+    Also block size can't be changed after OSD initialization without losing
+    data.
+
+    You must always specify block_size in etcd in /vitastor/config/global if
+    you change it so all clients can know about it.
+
+    OSD memory usage is roughly (SIZE / BLOCK * 68 bytes) which is roughly
+    544 MB per 1 TB of used disk space with the default 128 KB block size.
+  info_ru: |
+    Размер объектов (блоков данных), на которые делятся физические и виртуальные
+    диски в Vitastor. Одна из ключевых на данный момент настроек, влияет на
+    потребление памяти, объём избыточной записи (write amplification) и
+    эффективность распределения нагрузки по OSD.
+
+    Рекомендуемые по умолчанию размеры блока - 128 килобайт для SSD и 4
+    мегабайта для HDD. В принципе, для SSD можно тоже использовать 4 мегабайта,
+    это понизит использование памяти, но ухудшит распределение нагрузки и в
+    среднем увеличит WA.
+
+    OSD с разными размерами блока (например, SSD и SSD+HDD OSD) на данный
+    момент могут сосуществовать в рамках одного etcd только в виде двух независимых
+    кластеров Vitastor с разными etcd_prefix.
+
+    Также размер блока нельзя менять после инициализации OSD без потери данных.
+
+    Если вы меняете размер блока, обязательно прописывайте его в etcd в
+    /vitastor/config/global, дабы все клиенты его знали.
+
+    Потребление памяти OSD составляет примерно (РАЗМЕР / БЛОК * 68 байт),
+    т.е. примерно 544 МБ памяти на 1 ТБ занятого места на диске при
+    стандартном 128 КБ блоке.
+- name: bitmap_granularity
+  type: int
+  default: 4096
+  info: |
+    Required virtual disk write alignment ("sector size"). Must be a multiple
+    of disk_alignment. It's called bitmap granularity because Vitastor tracks
+    an allocation bitmap for each object containing 2 bits per each
+    (bitmap_granularity) bytes.
+
+    This parameter can't be changed after OSD initialization without losing
+    data. Also it's fixed for the whole Vitastor cluster i.e. two different
+    values can't be used in a single Vitastor cluster.
+
+    Clients MUST be aware of this parameter value, so put it into etcd key
+    /vitastor/config/global if you change it for any reason.
+  info_ru: |
+    Требуемое выравнивание записи на виртуальные диски (размер их "сектора").
+    Должен быть кратен disk_alignment. Называется гранулярностью битовой карты
+    потому, что Vitastor хранит битовую карту для каждого объекта, содержащую
+    по 2 бита на каждые (bitmap_granularity) байт.
+
+    Данный параметр нельзя менять после инициализации OSD без потери данных.
+    Также он фиксирован для всего кластера Vitastor, т.е. разные значения
+    не могут сосуществовать в одном кластере.
+
+    Клиенты ДОЛЖНЫ знать правильное значение этого параметра, так что если вы
+    его меняете, обязательно прописывайте изменённое значение в etcd в ключ
+    /vitastor/config/global.
+- name: immediate_commit
+  type: string
+  default: false
+  info: |
+    Another parameter which is really important for performance.
+
+    Desktop SSDs are very fast (100000+ iops) for simple random writes
+    without cache flush. However, they are really slow (only around 1000 iops)
+    if you try to fsync() each write, that is, when you want to guarantee that
+    each change gets immediately persisted to the physical media.
+
+    Server-grade SSDs with "Advanced/Enhanced Power Loss Protection" or with
+    "Supercapacitor-based Power Loss Protection", on the other hand, are equally
+    fast with and without fsync because their cache is protected from sudden
+    power loss by a built-in supercapacitor-based "UPS".
+
+    Some software-defined storage systems always fsync each write and thus are
+    really slow when used with desktop SSDs. Vitastor, however, can also
+    efficiently utilize desktop SSDs by postponing fsync until the client calls
+    it explicitly.
+
+    This is what this parameter regulates. When it's set to "all" the whole
+    Vitastor cluster commits each change to disks immediately and clients just
+    ignore fsyncs because they know for sure that they're unneeded. This reduces
+    the amount of network roundtrips performed by clients and improves
+    performance. So it's always better to use server grade SSDs with
+    supercapacitors even with Vitastor, especially given that they cost only
+    a bit more than desktop models.
+
+    There is also a common SATA SSD (and HDD too!) firmware bug (or feature)
+    that makes server SSDs which have supercapacitors slow with fsync. To check
+    if your SSDs are affected, compare benchmark results from `fio -name=test
+    -ioengine=libaio -direct=1 -bs=4k -rw=randwrite -iodepth=1` with and without
+    `-fsync=1`. Results should be the same. If fsync=1 result is worse you can
+    try to work around this bug by "disabling" drive write-back cache by running
+    `hdparm -W 0 /dev/sdXX` or `echo write through > /sys/block/sdXX/device/scsi_disk/*/cache_type`
+    (IMPORTANT: don't mistake it with `/sys/block/sdXX/queue/write_cache` - it's
+    unsafe to change by hand). The same may apply to newer HDDs with internal
+    SSD cache or "media-cache" - for example, a lot of Seagate EXOS drives have
+    it (they have internal SSD cache even though it's not stated in datasheets).
+
+    This parameter must be set both in etcd in /vitastor/config/global and in
+    OSD command line or configuration. Setting it to "all" or "small" requires
+    enabling disable_journal_fsync and disable_meta_fsync, setting it to "all"
+    also requires enabling disable_data_fsync.
+
+    TLDR: For optimal performance, set immediate_commit to "all" if you only use
+    SSDs with supercapacitor-based power loss protection (nonvolatile
+    write-through cache) for both data and journals in the whole Vitastor
+    cluster. Set it to "small" if you only use such SSDs for journals. Leave
+    empty if your drives have write-back cache.
+  info_ru: |
+    Ещё один важный для производительности параметр.
+
+    Модели SSD для настольных компьютеров очень быстрые (100000+ операций в
+    секунду) при простой случайной записи без сбросов кэша. Однако они очень
+    медленные (всего порядка 1000 iops), если вы пытаетесь сбрасывать кэш после
+    каждой записи, то есть, если вы пытаетесь гарантировать, что каждое
+    изменение физически записывается в энергонезависимую память.
+
+    С другой стороны, серверные SSD с конденсаторами - функцией, называемой
+    "Advanced/Enhanced Power Loss Protection" или просто "Supercapacitor-based
+    Power Loss Protection" - одинаково быстрые и со сбросом кэша, и без
+    него, потому что их кэш защищён от потери питания встроенным "источником
+    бесперебойного питания" на основе суперконденсаторов и на самом деле они
+    его никогда не сбрасывают.
+
+    Некоторые программные СХД всегда сбрасывают кэши дисков при каждой записи
+    и поэтому работают очень медленно с настольными SSD. Vitastor, однако, может
+    откладывать fsync до явного его вызова со стороны клиента и таким образом
+    эффективно утилизировать настольные SSD.
+
+    Данный параметр влияет как раз на это. Когда он установлен в значение "all",
+    весь кластер Vitastor мгновенно фиксирует каждое изменение на физические
+    носители и клиенты могут просто игнорировать запросы fsync, т.к. они точно
+    знают, что fsync-и не нужны. Это уменьшает число необходимых обращений к OSD
+    по сети и улучшает производительность. Поэтому даже с Vitastor лучше всегда
+    использовать только серверные модели SSD с суперконденсаторами, особенно
+    учитывая то, что стоят они ненамного дороже настольных.
+
+    Также в прошивках SATA SSD (и даже HDD!) очень часто встречается либо баг,
+    либо просто особенность логики, из-за которой серверные SSD, имеющие
+    конденсаторы и защиту от потери питания, всё равно медленно работают с
+    fsync. Чтобы понять, подвержены ли этой проблеме ваши SSD, сравните
+    результаты тестов `fio -name=test -ioengine=libaio -direct=1 -bs=4k
+    -rw=randwrite -iodepth=1` без и с опцией `-fsync=1`. Результаты должны
+    быть одинаковые. Если результат с `fsync=1` хуже, вы можете попробовать
+    обойти проблему, "отключив" кэш записи диска командой `hdparm -W 0 /dev/sdXX`
+    либо `echo write through > /sys/block/sdXX/device/scsi_disk/*/cache_type`
+    (ВАЖНО: не перепутайте с `/sys/block/sdXX/queue/write_cache` - этот параметр
+    менять руками небезопасно). Такая же проблема может встречаться и в новых
+    HDD-дисках с внутренним SSD или "медиа" кэшем - например, она встречается во
+    многих дисках Seagate EXOS (у них есть внутренний SSD-кэш, хотя это и не
+    указано в спецификациях).
+
+    Данный параметр нужно указывать и в etcd в /vitastor/config/global, и в
+    командной строке или конфигурации OSD. Значения "all" и "small" требуют
+    включения disable_journal_fsync и disable_meta_fsync, значение "all" также
+    требует включения disable_data_fsync.
+
+    Итого, вкратце: для оптимальной производительности установите
+    immediate_commit в значение "all", если вы используете в кластере только SSD
+    с суперконденсаторами и для данных, и для журналов. Если вы используете
+    такие SSD для всех журналов, но не для данных - можете установить параметр
+    в "small". Если и какие-то из дисков журналов имеют волатильный кэш записи -
+    оставьте параметр пустым.
+- name: client_dirty_limit
+  type: int
+  default: 33554432
+  info: |
+    Without immediate_commit=all this parameter sets the limit of "dirty"
+    (not committed by fsync) data allowed by the client before forcing an
+    additional fsync and committing the data. Also note that the client always
+    holds a copy of uncommitted data in memory so this setting also affects
+    RAM usage of clients.
+
+    This parameter doesn't affect OSDs themselves.
+  info_ru: |
+    При работе без immediate_commit=all - это лимит объёма "грязных" (не
+    зафиксированных fsync-ом) данных, при достижении которого клиент будет
+    принудительно вызывать fsync и фиксировать данные. Также стоит иметь в виду,
+    что в этом случае до момента fsync клиент хранит копию незафиксированных
+    данных в памяти, то есть, настройка влияет на потребление памяти клиентами.
+
+    Параметр не влияет на сами OSD.
--- a/docs/params/layout-osd.yml
+++ b/docs/params/layout-osd.yml
@@ -0,0 +1,205 @@
+- name: data_device
+  type: string
+  info: |
+    Path to the block device to use for data. It's highly recommendded to use
+    stable paths for all device names: `/dev/disk/by-partuuid/xxx...` instead
+    of just `/dev/sda` or `/dev/nvme0n1` to not mess up after server restart.
+    Files can also be used instead of block devices, but this is implemented
+    only for testing purposes and not for production.
+  info_ru: |
+    Путь к диску (блочному устройству) для хранения данных. Крайне рекомендуется
+    использовать стабильные пути: `/dev/disk/by-partuuid/xxx...` вместо простых
+    `/dev/sda` или `/dev/nvme0n1`, чтобы пути не могли спутаться после
+    перезагрузки сервера. Также вместо блочных устройств можно указывать файлы,
+    но это реализовано только для тестирования, а не для боевой среды.
+- name: meta_device
+  type: string
+  info: |
+    Path to the block device to use for the metadata. Metadata must be on a fast
+    SSD or performance will suffer. If this option is skipped, `data_device` is
+    used for the metadata.
+  info_ru: |
+    Путь к диску метаданных. Метаданные должны располагаться на быстром
+    SSD-диске, иначе производительность пострадает. Если эта опция не указана,
+    для метаданных используется `data_device`.
+- name: journal_device
+  type: string
+  info: |
+    Path to the block device to use for the journal. Journal must be on a fast
+    SSD or performance will suffer. If this option is skipped, `meta_device` is
+    used for the journal, and if it's also empty, journal is put on
+    `data_device`. It's almost always fine to put metadata and journal on the
+    same device, in this case you only need to set `meta_device`.
+  info_ru: |
+    Путь к диску журнала. Журнал должен располагаться на быстром SSD-диске,
+    иначе производительность пострадает. Если эта опция не указана,
+    для журнала используется `meta_device`, если же пуста и она, журнал
+    располагается на `data_device`. Нормально располагать журнал и метаданные
+    на одном устройстве, в этом случае достаточно указать только `meta_device`.
+- name: journal_offset
+  type: int
+  default: 0
+  info: Offset on the device in bytes where the journal is stored.
+  info_ru: Смещение на устройстве в байтах, по которому располагается журнал.
+- name: journal_size
+  type: int
+  info: |
+    Journal size in bytes. Doesn't have to be large, 16-32 MB is usually fine.
+    By default, the whole journal device will be used for the journal. You must
+    set it to some value manually (or use make-osd.sh) if you colocate the
+    journal with data or metadata.
+  info_ru: |
+    Размер журнала в байтах. Большим быть не обязан, 16-32 МБ обычно достаточно.
+    По умолчанию для журнала используется всё устройство журнала. Если же вы
+    размещаете журнал на устройстве данных или метаданных, то вы должны
+    установить эту опцию в какое-то значение сами (или использовать скрипт
+    make-osd.sh).
+- name: meta_offset
+  type: int
+  default: 0
+  info: |
+    Offset on the device in bytes where the metadata area is stored.
+    Again, set it to something if you colocate metadata with journal or data.
+  info_ru: |
+    Смещение на устройстве в байтах, по которому располагаются метаданные.
+    Эту опцию нужно задать, если метаданные у вас хранятся на том же
+    устройстве, что данные или журнал.
+- name: data_offset
+  type: int
+  default: 0
+  info: |
+    Offset on the device in bytes where the data area is stored.
+    Again, set it to something if you colocate data with journal or metadata.
+  info_ru: |
+    Смещение на устройстве в байтах, по которому располагаются данные.
+    Эту опцию нужно задать, если данные у вас хранятся на том же
+    устройстве, что метаданные или журнал.
+- name: data_size
+  type: int
+  info: |
+    Data area size in bytes. By default, the whole data device up to the end
+    will be used for the data area, but you can restrict it if you want to use
+    a smaller part. Note that there is no option to set metadata area size -
+    it's derived from the data area size.
+  info_ru: |
+    Размер области данных в байтах. По умолчанию под данные будет использована
+    вся доступная область устройства данных до конца устройства, но вы можете
+    использовать эту опцию, чтобы ограничить её меньшим размером. Заметьте, что
+    опции размера области метаданных нет - она вычисляется из размера области
+    данных автоматически.
+- name: meta_block_size
+  type: int
+  default: 4096
+  info: |
+    Physical block size of the metadata device. 4096 for most current
+    HDDs and SSDs.
+  info_ru: |
+    Размер физического блока устройства метаданных. 4096 для большинства
+    современных SSD и HDD.
+- name: journal_block_size
+  type: int
+  default: 4096
+  info: |
+    Physical block size of the journal device. Must be a multiple of
+    `disk_alignment`. 4096 for most current HDDs and SSDs.
+  info_ru: |
+    Размер физического блока устройства журнала. Должен быть кратен
+    `disk_alignment`. 4096 для большинства современных SSD и HDD.
+- name: disable_data_fsync
+  type: bool
+  default: false
+  info: |
+    Do not issue fsyncs to the data device, i.e. do not flush its cache.
+    Safe ONLY if your data device has write-through cache. If you disable
+    the cache yourself using `hdparm` or `scsi_disk/cache_type` then make sure
+    that the cache disable command is run every time before starting Vitastor
+    OSD, for example, in the systemd unit. See also `immediate_commit` option
+    for the instructions to disable cache and how to benefit from it.
+  info_ru: |
+    Не отправлять fsync-и устройству данных, т.е. не сбрасывать его кэш.
+    Безопасно, ТОЛЬКО если ваше устройство данных имеет кэш со сквозной
+    записью (write-through). Если вы отключаете кэш через `hdparm` или
+    `scsi_disk/cache_type`, то удостоверьтесь, что команда отключения кэша
+    выполняется перед каждым запуском Vitastor OSD, например, в systemd unit-е.
+    Смотрите также опцию `immediate_commit` для инструкций по отключению кэша
+    и о том, как из этого извлечь выгоду.
+- name: disable_meta_fsync
+  type: bool
+  default: false
+  info: |
+    Same as disable_data_fsync, but for the metadata device. If the metadata
+    device is not set or if the data device is used for the metadata the option
+    is ignored and disable_data_fsync value is used instead of it.
+  info_ru: |
+    То же, что disable_data_fsync, но для устройства метаданных. Если устройство
+    метаданных не задано или если оно равно устройству данных, значение опции
+    игнорируется и вместо него используется значение опции disable_data_fsync.
+- name: disable_journal_fsync
+  type: bool
+  default: false
+  info: |
+    Same as disable_data_fsync, but for the journal device. If the journal
+    device is not set or if the metadata device is used for the journal the
+    option is ignored and disable_meta_fsync value is used instead of it. If
+    the same device is used for data, metadata and journal the option is also
+    ignored and disable_data_fsync value is used instead of it.
+  info_ru: |
+    То же, что disable_data_fsync, но для устройства журнала. Если устройство
+    журнала не задано или если оно равно устройству метаданных, значение опции
+    игнорируется и вместо него используется значение опции disable_meta_fsync.
+    Если одно и то же устройство используется и под данные, и под журнал, и под
+    метаданные - значение опции также игнорируется и вместо него используется
+    значение опции disable_data_fsync.
+- name: disable_device_lock
+  type: bool
+  default: false
+  info: |
+    Do not lock data, metadata and journal block devices exclusively with
+    flock(). Though it's not recommended, but you can use it you want to run
+    multiple OSD with a single device and different offsets, without using
+    partitions.
+  info_ru: |
+    Не блокировать устройства данных, метаданных и журнала от открытия их
+    другими OSD с помощью flock(). Так делать не рекомендуется, но теоретически
+    вы можете это использовать, чтобы запускать несколько OSD на одном
+    устройстве с разными смещениями и без использования разделов.
+- name: disk_alignment
+  type: int
+  default: 4096
+  info: |
+    Required physical disk write alignment. Most current SSD and HDD drives
+    use 4 KB physical sectors even if they report 512 byte logical sector
+    size, so 4 KB is a good default setting.
+
+    Note, however, that physical sector size also affects WA, because with block
+    devices it's impossible to write anything smaller than a block. So, when
+    Vitastor has to write a single metadata entry that's only about 32 bytes in
+    size, it actually has to write the whole 4 KB sector.
+
+    Because of this it can actually be beneficial to use SSDs which work well
+    with 512 byte sectors and use 512 byte disk_alignment, journal_block_size
+    and meta_block_size. But the only SSD that may fit into this category is
+    Intel Optane (probably, not tested yet).
+
+    Clients don't need to be aware of disk_alignment, so it's not required to
+    put a modified value into etcd key /vitastor/config/global.
+  info_ru: |
+    Требуемое выравнивание записи на физические диски. Почти все современные
+    SSD и HDD диски используют 4 КБ физические секторы, даже если показывают
+    логический размер сектора 512 байт, поэтому 4 КБ - хорошее значение по
+    умолчанию.
+
+    Однако стоит понимать, что физический размер сектора тоже влияет на
+    избыточную запись (WA), потому что ничего меньше блока (сектора) на блочное
+    устройство записать невозможно. Таким образом, когда Vitastor-у нужно
+    записать на диск всего лишь одну 32-байтную запись метаданных, фактически
+    приходится перезаписывать 4 КБ сектор целиком.
+
+    Поэтому, на самом деле, может быть выгодно найти SSD, хорошо работающие с
+    меньшими, 512-байтными, блоками и использовать 512-байтные disk_alignment,
+    journal_block_size и meta_block_size. Однако единственные SSD, которые
+    теоретически могут попасть в эту категорию - это Intel Optane (но и это
+    пока не проверялось автором).
+
+    Клиентам не обязательно знать про disk_alignment, так что помещать значение
+    этого параметра в etcd в /vitastor/config/global не нужно.
--- a/docs/params/monitor.yml
+++ b/docs/params/monitor.yml
@@ -0,0 +1,65 @@
+- name: etcd_mon_ttl
+  type: sec
+  min: 10
+  default: 30
+  info: Monitor etcd lease refresh interval in seconds
+  info_ru: Интервал обновления etcd резервации (lease) монитором
+- name: etcd_mon_timeout
+  type: ms
+  default: 1000
+  info: etcd request timeout used by monitor
+  info_ru: Таймаут выполнения запросов к etcd от монитора
+- name: etcd_mon_retries
+  type: int
+  default: 5
+  info: Maximum number of attempts for one monitor etcd request
+  info_ru: Максимальное число попыток выполнения запросов к etcd монитором
+- name: mon_change_timeout
+  type: ms
+  min: 100
+  default: 1000
+  info: Optimistic retry interval for monitor etcd modification requests
+  info_ru: Время повтора при коллизиях при запросах модификации в etcd, производимых монитором
+- name: mon_stats_timeout
+  type: ms
+  min: 100
+  default: 1000
+  info: |
+    Interval for monitor to wait before updating aggregated statistics in
+    etcd after receiving OSD statistics updates
+  info_ru: |
+    Интервал, который монитор ожидает при изменении статистики по отдельным
+    OSD перед обновлением агрегированной статистики в etcd
+- name: osd_out_time
+  type: sec
+  default: 600
+  info: |
+    Time after which a failed OSD is removed from the data distribution.
+    I.e. time which the monitor waits before attempting to restore data
+    redundancy using other OSDs.
+  info_ru: |
+    Время, через которое отключенный OSD исключается из распределения данных.
+    То есть, время, которое монитор ожидает перед попыткой переместить данные
+    на другие OSD и таким образом восстановить избыточность хранения.
+- name: placement_levels
+  type: json
+  default: '`{"host":100,"osd":101}`'
+  info: |
+    Levels for the placement tree. You can define arbitrary tree levels by
+    defining them in this parameter. The configuration parameter value should
+    contain a JSON object with level names as keys and integer priorities as
+    values.  Smaller priority means higher level in tree. For example,
+    "datacenter" should have smaller priority than "osd". "host" and "osd"
+    levels are always predefined and can't be removed. If one of them is not
+    present in the configuration, then it is defined with the default priority
+    (100 for "host", 101 for "osd").
+  info_ru: |
+    Определения уровней для дерева размещения OSD. Вы можете определять
+    произвольные уровни, помещая их в данный параметр конфигурации. Значение
+    параметра должно содержать JSON-объект, ключи которого будут являться
+    названиями уровней, а значения - целочисленными приоритетами. Меньшие
+    приоритеты соответствуют верхним уровням дерева. Например, уровень
+    "датацентр" должен иметь меньший приоритет, чем "OSD". Уровни с названиями
+    "host" и "osd" являются предопределёнными и не могут быть удалены. Если
+    один из них отсутствует в конфигурации, он доопределяется с приоритетом по
+    умолчанию (100 для уровня "host", 101 для "osd").
--- a/docs/params/network.yml
+++ b/docs/params/network.yml
@@ -0,0 +1,225 @@
+- name: tcp_header_buffer_size
+  type: int
+  default: 65536
+  info: |
+    Size of the buffer used to read data using an additional copy. Vitastor
+    packet headers are 128 bytes, payload is always at least 4 KB, so it is
+    usually beneficial to try to read multiple packets at once even though
+    it requires to copy the data an additional time. The rest of each packet
+    is received without an additional copy. You can try to play with this
+    parameter and see how it affects random iops and linear bandwidth if you
+    want.
+  info_ru: |
+    Размер буфера для чтения данных с дополнительным копированием. Пакеты
+    Vitastor содержат 128-байтные заголовки, за которыми следуют данные размером
+    от 4 КБ и для мелких операций ввода-вывода обычно выгодно за 1 вызов читать
+    сразу несколько пакетов, даже не смотря на то, что это требует лишний раз
+    скопировать данные. Часть каждого пакета за пределами значения данного
+    параметра читается без дополнительного копирования. Вы можете попробовать
+    поменять этот параметр и посмотреть, как он влияет на производительность
+    случайного и линейного доступа.
+- name: use_sync_send_recv
+  type: bool
+  default: false
+  info: |
+    If true, synchronous send/recv syscalls are used instead of io_uring for
+    socket communication. Useless for OSDs because they require io_uring anyway,
+    but may be required for clients with old kernel versions.
+  info_ru: |
+    Если установлено в истину, то вместо io_uring для передачи данных по сети
+    будут использоваться обычные синхронные системные вызовы send/recv. Для OSD
+    это бессмысленно, так как OSD в любом случае нуждается в io_uring, но, в
+    принципе, это может применяться для клиентов со старыми версиями ядра.
+- name: use_rdma
+  type: bool
+  default: true
+  info: |
+    Try to use RDMA for communication if it's available. Disable if you don't
+    want Vitastor to use RDMA. RDMA increases the performance, but TCP-only
+    clients can still talk to an RDMA-enabled cluster, so you don't need to
+    make sure that all clients support RDMA when enabling it.
+  info_ru: |
+    Пытаться использовать RDMA для связи при наличии доступных устройств.
+    Отключите, если вы не хотите, чтобы Vitastor использовал RDMA.
+    RDMA улучшает производительность, но 
+    Клиенты и клиентов and TCP-only clients in the cluster at the
+    same time - TCP-only clients are still able to use an RDMA-enabled cluster.
+- name: rdma_device
+  type: string
+  info: |
+    RDMA device name to use for Vitastor OSD communications (for example,
+    "rocep5s0f0"). Please note that Vitastor RDMA requires Implicit On-Demand
+    Paging (Implicit ODP) and Scatter/Gather (SG) support from the RDMA device
+    to work. For example, Mellanox ConnectX-3 and older adapters don't have
+    Implicit ODP, so they're unsupported by Vitastor. Run `ibv_devinfo -v` as
+    root to list available RDMA devices and their features.
+  info_ru: |
+    Название RDMA-устройства для связи с Vitastor OSD (например, "rocep5s0f0").
+    Имейте в виду, что поддержка RDMA в Vitastor требует функций устройства
+    Implicit On-Demand Paging (Implicit ODP) и Scatter/Gather (SG). Например,
+    адаптеры Mellanox ConnectX-3 и более старые не поддерживают Implicit ODP и
+    потому не поддерживаются в Vitastor. Запустите `ibv_devinfo -v` от имени
+    суперпользователя, чтобы посмотреть список доступных RDMA-устройств, их
+    параметры и возможности.
+- name: rdma_port_num
+  type: int
+  default: 1
+  info: |
+    RDMA device port number to use. Only for devices that have more than 1 port.
+    See `phys_port_cnt` in `ibv_devinfo -v` output to determine how many ports
+    your device has.
+  info_ru: |
+    Номер порта RDMA-устройства, который следует использовать. Имеет смысл
+    только для устройств, у которых более 1 порта. Чтобы узнать, сколько портов
+    у вашего адаптера, посмотрите `phys_port_cnt` в выводе команды
+    `ibv_devinfo -v`.
+- name: rdma_gid_index
+  type: int
+  default: 0
+  info: |
+    Global address identifier index of the RDMA device to use. Different GID
+    indexes may correspond to different protocols like RoCEv1, RoCEv2 and iWARP.
+    Search for "GID" in `ibv_devinfo -v` output to determine which GID index
+    you need.
+
+    **IMPORTANT:** If you want to use RoCEv2 (as recommended) then the correct
+    rdma_gid_index is usually 1 (IPv6) or 3 (IPv4).
+  info_ru: |
+    Номер глобального идентификатора адреса RDMA-устройства, который следует
+    использовать. Разным gid_index могут соответствовать разные протоколы связи:
+    RoCEv1, RoCEv2, iWARP. Чтобы понять, какой нужен вам - смотрите строчки со
+    словом "GID" в выводе команды `ibv_devinfo -v`.
+
+    **ВАЖНО:** Если вы хотите использовать RoCEv2 (как мы и рекомендуем), то
+    правильный rdma_gid_index, как правило, 1 (IPv6) или 3 (IPv4).
+- name: rdma_mtu
+  type: int
+  default: 4096
+  info: |
+    RDMA Path MTU to use. Must be 1024, 2048 or 4096. There is usually no
+    sense to change it from the default 4096.
+  info_ru: |
+    Максимальная единица передачи (Path MTU) для RDMA. Должно быть равно 1024,
+    2048 или 4096. Обычно нет смысла менять значение по умолчанию, равное 4096.
+- name: rdma_max_sge
+  type: int
+  default: 128
+  info: |
+    Maximum number of scatter/gather entries to use for RDMA. OSDs negotiate
+    the actual value when establishing connection anyway, so it's usually not
+    required to change this parameter.
+  info_ru: |
+    Максимальное число записей разделения/сборки (scatter/gather) для RDMA.
+    OSD в любом случае согласовывают реальное значение при установке соединения,
+    так что менять этот параметр обычно не нужно.
+- name: rdma_max_msg
+  type: int
+  default: 1048576
+  info: Maximum size of a single RDMA send or receive operation in bytes.
+  info_ru: Максимальный размер одной RDMA-операции отправки или приёма.
+- name: rdma_max_recv
+  type: int
+  default: 8
+  info: |
+    Maximum number of parallel RDMA receive operations. Note that this number
+    of receive buffers `rdma_max_msg` in size are allocated for each client,
+    so this setting actually affects memory usage. This is because RDMA receive
+    operations are (sadly) still not zero-copy in Vitastor. It may be fixed in
+    later versions.
+  info_ru: |
+    Максимальное число параллельных RDMA-операций получения данных. Следует
+    иметь в виду, что данное число буферов размером `rdma_max_msg` выделяется
+    для каждого подключённого клиентского соединения, так что данная настройка
+    влияет на потребление памяти. Это так потому, что RDMA-приём данных в
+    Vitastor, увы, всё равно не является zero-copy, т.е. всё равно 1 раз
+    копирует данные в памяти. Данная особенность, возможно, будет исправлена в
+    более новых версиях Vitastor.
+- name: peer_connect_interval
+  type: sec
+  min: 1
+  default: 5
+  info: Interval before attempting to reconnect to an unavailable OSD.
+  info_ru: Время ожидания перед повторной попыткой соединиться с недоступным OSD.
+- name: peer_connect_timeout
+  type: sec
+  min: 1
+  default: 5
+  info: Timeout for OSD connection attempts.
+  info_ru: Максимальное время ожидания попытки соединения с OSD.
+- name: osd_idle_timeout
+  type: sec
+  min: 1
+  default: 5
+  info: |
+    OSD connection inactivity time after which clients and other OSDs send
+    keepalive requests to check state of the connection.
+  info_ru: |
+    Время неактивности соединения с OSD, после которого клиенты или другие OSD
+    посылают запрос проверки состояния соединения.
+- name: osd_ping_timeout
+  type: sec
+  min: 1
+  default: 5
+  info: |
+    Maximum time to wait for OSD keepalive responses. If an OSD doesn't respond
+    within this time, the connection to it is dropped and a reconnection attempt
+    is scheduled.
+  info_ru: |
+    Максимальное время ожидания ответа на запрос проверки состояния соединения.
+    Если OSD не отвечает за это время, соединение отключается и производится
+    повторная попытка соединения.
+- name: up_wait_retry_interval
+  type: ms
+  min: 50
+  default: 500
+  info: |
+    OSDs respond to clients with a special error code when they receive I/O
+    requests for a PG that's not synchronized and started. This parameter sets
+    the time for the clients to wait before re-attempting such I/O requests.
+  info_ru: |
+    Когда OSD получают от клиентов запросы ввода-вывода, относящиеся к не
+    поднятым на данный момент на них PG, либо к PG в процессе синхронизации,
+    они отвечают клиентам специальным кодом ошибки, означающим, что клиент
+    должен некоторое время подождать перед повторением запроса. Именно это время
+    ожидания задаёт данный параметр.
+- name: max_etcd_attempts
+  type: int
+  default: 5
+  info: |
+    Maximum number of attempts for etcd requests which can't be retried
+    indefinitely.
+  info_ru: |
+    Максимальное число попыток выполнения запросов к etcd для тех запросов,
+    которые нельзя повторять бесконечно.
+- name: etcd_quick_timeout
+  type: ms
+  default: 1000
+  info: |
+    Timeout for etcd requests which should complete quickly, like lease refresh.
+  info_ru: |
+    Максимальное время выполнения запросов к etcd, которые должны завершаться
+    быстро, таких, как обновление резервации (lease).
+- name: etcd_slow_timeout
+  type: ms
+  default: 5000
+  info: Timeout for etcd requests which are allowed to wait for some time.
+  info_ru: |
+    Максимальное время выполнения запросов к etcd, для которых не обязательно
+    гарантировать быстрое выполнение.
+- name: etcd_keepalive_timeout
+  type: sec
+  default: max(30, etcd_report_interval*2)
+  info: |
+    Timeout for etcd connection HTTP Keep-Alive. Should be higher than
+    etcd_report_interval to guarantee that keepalive actually works.
+  info_ru: |
+    Таймаут для HTTP Keep-Alive в соединениях к etcd. Должен быть больше, чем
+    etcd_report_interval, чтобы keepalive гарантированно работал.
+- name: etcd_ws_keepalive_timeout
+  type: sec
+  default: 30
+  info: |
+    etcd websocket ping interval required to keep the connection alive and
+    detect disconnections quickly.
+  info_ru: |
+    Интервал проверки живости вебсокет-подключений к etcd.
--- a/docs/params/osd.yml
+++ b/docs/params/osd.yml
@@ -0,0 +1,341 @@
+- name: etcd_report_interval
+  type: sec
+  default: 5
+  info: |
+    Interval at which OSDs report their state to etcd. Affects OSD lease time
+    and thus the failover speed. Lease time is equal to this parameter value
+    plus max_etcd_attempts * etcd_quick_timeout because it should be guaranteed
+    that every OSD always refreshes its lease in time.
+  info_ru: |
+    Интервал, с которым OSD обновляет своё состояние в etcd. Значение параметра
+    влияет на время резервации (lease) OSD и поэтому на скорость переключения
+    при падении OSD. Время lease равняется значению этого параметра плюс
+    max_etcd_attempts * etcd_quick_timeout.
+- name: run_primary
+  type: bool
+  default: true
+  info: |
+    Start primary OSD logic on this OSD. As of now, can be turned off only for
+    debugging purposes. It's possible to implement additional feature for the
+    monitor which may allow to separate primary and secondary OSDs, but it's
+    unclear why anyone could need it, so it's not implemented.
+  info_ru: |
+    Запускать логику первичного OSD на данном OSD. На данный момент отключать
+    эту опцию может иметь смысл только в целях отладки. В теории, можно
+    реализовать дополнительный режим для монитора, который позволит отделять
+    первичные OSD от вторичных, но пока не понятно, зачем это может кому-то
+    понадобиться, поэтому это не реализовано.
+- name: osd_network
+  type: string or array of strings
+  type_ru: строка или массив строк
+  info: |
+    Network mask of the network (IPv4 or IPv6) to use for OSDs. Note that
+    although it's possible to specify multiple networks here, this does not
+    mean that OSDs will create multiple listening sockets - they'll only
+    pick the first matching address of an UP + RUNNING interface. Separate
+    networks for cluster and client connections are also not implemented, but
+    they are mostly useless anyway, so it's not a big deal.
+  info_ru: |
+    Маска подсети (IPv4 или IPv6) для использования для соединений с OSD.
+    Имейте в виду, что хотя сейчас и можно передать в этот параметр несколько
+    подсетей, это не означает, что OSD будут создавать несколько слушающих
+    сокетов - они лишь будут выбирать адрес первого поднятого (состояние UP +
+    RUNNING), подходящий под заданную маску. Также не реализовано разделение
+    кластерной и публичной сетей OSD. Правда, от него обычно всё равно довольно
+    мало толку, так что особенной проблемы в этом нет.
+- name: bind_address
+  type: string
+  default: "0.0.0.0"
+  info: |
+    Instead of the network mask, you can also set OSD listen address explicitly
+    using this parameter. May be useful if you want to start OSDs on interfaces
+    that are not UP + RUNNING.
+  info_ru: |
+    Этим параметром можно явным образом задать адрес, на котором будет ожидать
+    соединений OSD (вместо использования маски подсети). Может быть полезно,
+    например, чтобы запускать OSD на неподнятых интерфейсах (не UP + RUNNING).
+- name: bind_port
+  type: int
+  info: |
+    By default, OSDs pick random ports to use for incoming connections
+    automatically. With this option you can set a specific port for a specific
+    OSD by hand.
+  info_ru: |
+    По умолчанию OSD сами выбирают случайные порты для входящих подключений.
+    С помощью данной опции вы можете задать порт для отдельного OSD вручную.
+- name: autosync_interval
+  type: sec
+  default: 5
+  info: |
+    Time interval at which automatic fsyncs/flushes are issued by each OSD when
+    the immediate_commit mode if disabled. fsyncs are required because without
+    them OSDs quickly fill their journals, become unable to clear them and
+    stall. Also this option limits the amount of recent uncommitted changes
+    which OSDs may lose in case of a power outage in case when clients don't
+    issue fsyncs at all.
+  info_ru: |
+    Временной интервал отправки автоматических fsync-ов (операций очистки кэша)
+    каждым OSD для случая, когда режим immediate_commit отключён. fsync-и нужны
+    OSD, чтобы успевать очищать журнал - без них OSD быстро заполняют журналы и
+    перестают обрабатывать операции записи. Также эта опция ограничивает объём
+    недавних незафиксированных изменений, которые OSD могут терять при
+    отключении питания, если клиенты вообще не отправляют fsync.
+- name: autosync_writes
+  type: int
+  default: 128
+  info: |
+    Same as autosync_interval, but sets the maximum number of uncommitted write
+    operations before issuing an fsync operation internally.
+  info_ru: |
+    Аналогично autosync_interval, но задаёт не временной интервал, а
+    максимальное количество незафиксированных операций записи перед
+    принудительной отправкой fsync-а.
+- name: recovery_queue_depth
+  type: int
+  default: 4
+  info: |
+    Maximum recovery operations per one primary OSD at any given moment of time.
+    Currently it's the only parameter available to tune the speed or recovery
+    and rebalancing, but it's planned to implement more.
+  info_ru: |
+    Максимальное число операций восстановления на одном первичном OSD в любой
+    момент времени. На данный момент единственный параметр, который можно менять
+    для ускорения или замедления восстановления и перебалансировки данных, но
+    в планах реализация других параметров.
+- name: recovery_sync_batch
+  type: int
+  default: 16
+  info: Maximum number of recovery operations before issuing an additional fsync.
+  info_ru: Максимальное число операций восстановления перед дополнительным fsync.
+- name: readonly
+  type: bool
+  default: false
+  info: |
+    Read-only mode. If this is enabled, an OSD will never issue any writes to
+    the underlying device. This may be useful for recovery purposes.
+  info_ru: |
+    Режим "только чтение". Если включить этот режим, OSD не будет писать ничего
+    на диск. Может быть полезно в целях восстановления.
+- name: no_recovery
+  type: bool
+  default: false
+  info: |
+    Disable automatic background recovery of objects. Note that it doesn't
+    affect implicit recovery of objects happening during writes - a write is
+    always made to a full set of at least pg_minsize OSDs.
+  info_ru: |
+    Отключить автоматическое фоновое восстановление объектов. Обратите внимание,
+    что эта опция не отключает восстановление объектов, происходящее при
+    записи - запись всегда производится в полный набор из как минимум pg_minsize
+    OSD.
+- name: no_rebalance
+  type: bool
+  default: false
+  info: |
+    Disable background movement of data between different OSDs. Disabling it
+    means that PGs in the `has_misplaced` state will be left in it indefinitely.
+  info_ru: |
+    Отключить фоновое перемещение объектов между разными OSD. Отключение
+    означает, что PG, находящиеся в состоянии `has_misplaced`, будут оставлены
+    в нём на неопределённый срок.
+- name: print_stats_interval
+  type: sec
+  default: 3
+  info: |
+    Time interval at which OSDs print simple human-readable operation
+    statistics on stdout.
+  info_ru: |
+    Временной интервал, с которым OSD печатают простую человекочитаемую
+    статистику выполнения операций в стандартный вывод.
+- name: slow_log_interval
+  type: sec
+  default: 10
+  info: |
+    Time interval at which OSDs dump slow or stuck operations on stdout, if
+    they're any. Also it's the time after which an operation is considered
+    "slow".
+  info_ru: |
+    Временной интервал, с которым OSD выводят в стандартный вывод список
+    медленных или зависших операций, если таковые имеются. Также время, при
+    превышении которого операция считается "медленной".
+- name: max_write_iodepth
+  type: int
+  default: 128
+  info: |
+    Parallel client write operation limit per one OSD. Operations that exceed
+    this limit are pushed to a temporary queue instead of being executed
+    immediately.
+  info_ru: |
+    Максимальное число одновременных клиентских операций записи на один OSD.
+    Операции, превышающие этот лимит, не исполняются сразу, а сохраняются во
+    временной очереди.
+- name: min_flusher_count
+  type: int
+  default: 1
+  info: |
+    Flusher is a micro-thread that moves data from the journal to the data
+    area of the device. Their number is auto-tuned between minimum and maximum.
+    Minimum number is set by this parameter.
+  info_ru: |
+    Flusher - это микро-поток (корутина), которая копирует данные из журнала в
+    основную область устройства данных. Их число настраивается динамически между
+    минимальным и максимальным значением. Этот параметр задаёт минимальное число.
+- name: max_flusher_count
+  type: int
+  default: 256
+  info: |
+    Maximum number of journal flushers (see above min_flusher_count).
+  info_ru: |
+    Максимальное число микро-потоков очистки журнала (см. выше min_flusher_count).
+- name: inmemory_metadata
+  type: bool
+  default: true
+  info: |
+    This parameter makes Vitastor always keep metadata area of the block device
+    in memory. It's required for good performance because it allows to avoid
+    additional read-modify-write cycles during metadata modifications. Metadata
+    area size is currently roughly 224 MB per 1 TB of data. You can turn it off
+    to reduce memory usage by this value, but it will hurt performance. This
+    restriction is likely to be removed in the future along with the upgrade
+    of the metadata storage scheme.
+  info_ru: |
+    Данный параметр заставляет Vitastor всегда держать область метаданных диска
+    в памяти. Это нужно, чтобы избегать дополнительных операций чтения с диска
+    при записи. Размер области метаданных на данный момент составляет примерно
+    224 МБ на 1 ТБ данных. При включении потребление памяти снизится примерно
+    на эту величину, но при этом также снизится и производительность. В будущем,
+    после обновления схемы хранения метаданных, это ограничение, скорее всего,
+    будет ликвидировано.
+- name: inmemory_journal
+  type: bool
+  default: true
+  info: |
+    This parameter make Vitastor always keep journal area of the block
+    device in memory. Turning it off will, again, reduce memory usage, but
+    hurt performance because flusher coroutines will have to read data from
+    the disk back before copying it into the main area. The memory usage benefit
+    is typically very small because it's sufficient to have 16-32 MB journal
+    for SSD OSDs. However, in theory it's possible that you'll want to turn it
+    off for hybrid (HDD+SSD) OSDs with large journals on quick devices.
+  info_ru: |
+    Данный параметр заставляет Vitastor всегда держать в памяти журналы OSD.
+    Отключение параметра, опять же, снижает потребление памяти, но ухудшает
+    производительность, так как для копирования данных из журнала в основную
+    область устройства OSD будут вынуждены читать их обратно с диска. Выигрыш
+    по памяти при этом обычно крайне низкий, так как для SSD OSD обычно
+    достаточно 16- или 32-мегабайтного журнала. Однако в теории отключение
+    параметра может оказаться полезным для гибридных OSD (HDD+SSD) с большими
+    журналами, расположенными на быстром по сравнению с HDD устройстве.
+- name: journal_sector_buffer_count
+  type: int
+  default: 32
+  info: |
+    Maximum number of buffers that can be used for writing journal metadata
+    blocks. The only situation when you should increase it to a larger value
+    is when you enable journal_no_same_sector_overwrites. In this case set
+    it to, for example, 1024.
+  info_ru: |
+    Максимальное число буферов, разрешённых для использования под записываемые
+    в журнал блоки метаданных. Единственная ситуация, в которой этот параметр
+    нужно менять - это если вы включаете journal_no_same_sector_overwrites. В
+    этом случае установите данный параметр, например, в 1024.
+- name: journal_no_same_sector_overwrites
+  type: bool
+  default: false
+  info: |
+    Enable this option for SSDs like Intel D3-S4510 and D3-S4610 which REALLY
+    don't like when a program overwrites the same sector multiple times in a
+    row and slow down significantly (from 25000+ iops to ~3000 iops). When
+    this option is set, Vitastor will always move to the next sector of the
+    journal after writing it instead of possibly overwriting it the second time.
+  info_ru: |
+    Включайте данную опцию для SSD вроде Intel D3-S4510 и D3-S4610, которые
+    ОЧЕНЬ не любят, когда ПО перезаписывает один и тот же сектор несколько раз
+    подряд. Такие SSD при многократной перезаписи одного и того же сектора
+    сильно замедляются - условно, с 25000 и более iops до 3000 iops. Когда
+    данная опция установлена, Vitastor всегда переходит к следующему сектору
+    журнала после записи вместо потенциально повторной перезаписи того же
+    самого сектора.
+- name: throttle_small_writes
+  type: bool
+  default: false
+  info: |
+    Enable soft throttling of small journaled writes. Useful for hybrid OSDs
+    with fast journal/metadata devices and slow data devices. The idea is that
+    small writes complete very quickly because they're first written to the
+    journal device, but moving them to the main device is slow. So if an OSD
+    allows clients to issue a lot of small writes it will perform very good
+    for several seconds and then the journal will fill up and the performance
+    will drop to almost zero. Throttling is meant to prevent this problem by
+    artifically slowing quick writes down based on the amount of free space in
+    the journal. When throttling is used, the performance of small writes will
+    decrease smoothly instead of abrupt drop at the moment when the journal
+    fills up.
+  info_ru: |
+    Разрешить мягкое ограничение скорости журналируемой записи. Полезно для
+    гибридных OSD с быстрыми устройствами метаданных и медленными устройствами
+    данных. Идея заключается в том, что мелкие записи в этой ситуации могут
+    завершаться очень быстро, так как они изначально записываются на быстрое
+    журнальное устройство (SSD). Но перемещать их потом на основное медленное
+    устройство долго. Поэтому если OSD быстро примет от клиентов очень много
+    мелких операций записи, он быстро заполнит свой журнал, после чего
+    производительность записи резко упадёт практически до нуля. Ограничение
+    скорости записи призвано решить эту проблему с помощью искусственного
+    замедления операций записи на основании объёма свободного места в журнале.
+    Когда эта опция включена, производительность мелких операций записи будет
+    снижаться плавно, а не резко в момент окончательного заполнения журнала.
+- name: throttle_target_iops
+  type: int
+  default: 100
+  info: |
+    Target maximum number of throttled operations per second under the condition
+    of full journal. Set it to approximate random write iops of your data devices
+    (HDDs).
+  info_ru: |
+    Расчётное максимальное число ограничиваемых операций в секунду при условии
+    отсутствия свободного места в журнале. Устанавливайте приблизительно равным
+    максимальной производительности случайной записи ваших устройств данных
+    (HDD) в операциях в секунду.
+- name: throttle_target_mbs
+  type: int
+  default: 100
+  info: |
+    Target maximum bandwidth in MB/s of throttled operations per second under
+    the condition of full journal. Set it to approximate linear write
+    performance of your data devices (HDDs).
+  info_ru: |
+    Расчётный максимальный размер в МБ/с ограничиваемых операций в секунду при
+    условии отсутствия свободного места в журнале. Устанавливайте приблизительно
+    равным максимальной производительности линейной записи ваших устройств
+    данных (HDD).
+- name: throttle_target_parallelism
+  type: int
+  default: 1
+  info: |
+    Target maximum parallelism of throttled operations under the condition of
+    full journal. Set it to approximate internal parallelism of your data
+    devices (1 for HDDs, 4-8 for SSDs).
+  info_ru: |
+    Расчётный максимальный параллелизм ограничиваемых операций в секунду при
+    условии отсутствия свободного места в журнале. Устанавливайте приблизительно
+    равным внутреннему параллелизму ваших устройств данных (1 для HDD, 4-8
+    для SSD).
+- name: throttle_threshold_us
+  type: us
+  default: 50
+  info: |
+    Minimal computed delay to be applied to throttled operations. Usually
+    doesn't need to be changed.
+  info_ru: |
+    Минимальная применимая к ограничиваемым операциям задержка. Обычно не
+    требует изменений.
+- name: osd_memlock
+  type: bool
+  default: false
+  info: >
+    Lock all OSD memory to prevent it from being unloaded into swap with
+    mlockall(). Requires sufficient ulimit -l (max locked memory).
+  info_ru: >
+    Блокировать всю память OSD с помощью mlockall, чтобы запретить её выгрузку
+    в пространство подкачки. Требует достаточного значения ulimit -l (лимита
+    заблокированной памяти).
--- a/mon/mon.js
+++ b/mon/mon.js
@@ -83,13 +83,13 @@ const etcd_tree = {
            osd_idle_timeout: 5, // seconds. min: 1
            osd_ping_timeout: 5, // seconds. min: 1
            up_wait_retry_interval: 500, // ms. min: 50
-            // osd
-            etcd_report_interval: 5, // seconds
            max_etcd_attempts: 5,
            etcd_quick_timeout: 1000, // ms
            etcd_slow_timeout: 5000, // ms
-            etcd_keepalive_timeout: 30, // seconds, default is min(30, etcd_report_interval*2)
+            etcd_keepalive_timeout: 30, // seconds, default is max(30, etcd_report_interval*2)
            etcd_ws_keepalive_interval: 30, // seconds
+            // osd
+            etcd_report_interval: 5, // seconds
            run_primary: true,
            osd_network: null, // "192.168.7.0/24" or an array of masks
            bind_address: "0.0.0.0",
@@ -104,6 +104,7 @@ const etcd_tree = {
            no_rebalance: false,
            print_stats_interval: 3,
            slow_log_interval: 10,
+            osd_memlock: false,
            // blockstore - fixed in superblock
            block_size,
            disk_alignment,
@@ -130,6 +131,11 @@ const etcd_tree = {
            inmemory_journal,
            journal_sector_buffer_count,
            journal_no_same_sector_overwrites,
+            throttle_small_writes: false,
+            throttle_target_iops: 100,
+            throttle_target_mbs: 100,
+            throttle_target_parallelism: 1,
+            throttle_threshold_us: 50,
        }, */
        global: {},
        /* node_placement: {
@@ -1339,21 +1345,30 @@ class Mon
        const tm = prev_stats ? BigInt(timestamp - prev_stats.timestamp) : 0;
        for (const op in op_stats)
        {
-            op_stats[op].bps = prev_stats ? (op_stats[op].bytes - prev_stats.op_stats[op].bytes) * 1000n / tm : 0;
-            op_stats[op].iops = prev_stats ? (op_stats[op].count - prev_stats.op_stats[op].count) * 1000n / tm : 0;
-            op_stats[op].lat = prev_stats ? (op_stats[op].usec - prev_stats.op_stats[op].usec)
-                / ((op_stats[op].count - prev_stats.op_stats[op].count) || 1n) : 0;
+            if (prev_stats && prev_stats.op_stats && prev_stats.op_stats[op])
+            {
+                op_stats[op].bps = (op_stats[op].bytes - prev_stats.op_stats[op].bytes) * 1000n / tm;
+                op_stats[op].iops = (op_stats[op].count - prev_stats.op_stats[op].count) * 1000n / tm;
+                op_stats[op].lat = (op_stats[op].usec - prev_stats.op_stats[op].usec)
+                    / ((op_stats[op].count - prev_stats.op_stats[op].count) || 1n);
+            }
        }
        for (const op in subop_stats)
        {
-            subop_stats[op].iops = prev_stats ? (subop_stats[op].count - prev_stats.subop_stats[op].count) * 1000n / tm : 0;
-            subop_stats[op].lat = prev_stats ? (subop_stats[op].usec - prev_stats.subop_stats[op].usec)
-                / ((subop_stats[op].count - prev_stats.subop_stats[op].count) || 1n) : 0;
+            if (prev_stats && prev_stats.subop_stats && prev_stats.subop_stats[op])
+            {
+                subop_stats[op].iops = (subop_stats[op].count - prev_stats.subop_stats[op].count) * 1000n / tm;
+                subop_stats[op].lat = (subop_stats[op].usec - prev_stats.subop_stats[op].usec)
+                    / ((subop_stats[op].count - prev_stats.subop_stats[op].count) || 1n);
+            }
        }
        for (const op in recovery_stats)
        {
-            recovery_stats[op].bps = prev_stats ? (recovery_stats[op].bytes - prev_stats.recovery_stats[op].bytes) * 1000n / tm : 0;
-            recovery_stats[op].iops = prev_stats ? (recovery_stats[op].count - prev_stats.recovery_stats[op].count) * 1000n / tm : 0;
+            if (prev_stats && prev_stats.recovery_stats && prev_stats.recovery_stats[op])
+            {
+                recovery_stats[op].bps = (recovery_stats[op].bytes - prev_stats.recovery_stats[op].bytes) * 1000n / tm;
+                recovery_stats[op].iops = (recovery_stats[op].count - prev_stats.recovery_stats[op].count) * 1000n / tm;
+            }
        }
        return { op_stats, subop_stats, recovery_stats };
    }
--- a/patches/cinder-vitastor.py
+++ b/patches/cinder-vitastor.py
@@ -50,7 +50,7 @@ from cinder.volume import configuration
 from cinder.volume import driver
 from cinder.volume import volume_utils

-VERSION = '0.6.12'
+VERSION = '0.6.15'

 LOG = logging.getLogger(__name__)

--- a/rpm/build-tarball.sh
+++ b/rpm/build-tarball.sh
@@ -25,4 +25,4 @@ rm fio
 mv fio-copy fio
 FIO=`rpm -qi fio | perl -e 'while(<>) { /^Epoch[\s:]+(\S+)/ && print "$1:"; /^Version[\s:]+(\S+)/ && print $1; /^Release[\s:]+(\S+)/ && print "-$1"; }'`
 perl -i -pe 's/(Requires:\s*fio)([^\n]+)?/$1 = '$FIO'/' $VITASTOR/rpm/vitastor-el$EL.spec
-tar --transform 's#^#vitastor-0.6.12/#' --exclude 'rpm/*.rpm' -czf $VITASTOR/../vitastor-0.6.12$(rpm --eval '%dist').tar.gz *
+tar --transform 's#^#vitastor-0.6.15/#' --exclude 'rpm/*.rpm' -czf $VITASTOR/../vitastor-0.6.15$(rpm --eval '%dist').tar.gz *
--- a/rpm/vitastor-el7.Dockerfile
+++ b/rpm/vitastor-el7.Dockerfile
@@ -34,7 +34,7 @@ ADD . /root/vitastor
 RUN set -e; \
    cd /root/vitastor/rpm; \
    sh build-tarball.sh; \
-    cp /root/vitastor-0.6.12.el7.tar.gz ~/rpmbuild/SOURCES; \
+    cp /root/vitastor-0.6.15.el7.tar.gz ~/rpmbuild/SOURCES; \
    cp vitastor-el7.spec ~/rpmbuild/SPECS/vitastor.spec; \
    cd ~/rpmbuild/SPECS/; \
    rpmbuild -ba vitastor.spec; \
--- a/rpm/vitastor-el7.spec
+++ b/rpm/vitastor-el7.spec
@@ -1,11 +1,11 @@
 Name:           vitastor
-Version:        0.6.12
+Version:        0.6.15
 Release:        1%{?dist}
 Summary:        Vitastor, a fast software-defined clustered block storage

 License:        Vitastor Network Public License 1.1
 URL:            https://vitastor.io/
-Source0:        vitastor-0.6.12.el7.tar.gz
+Source0:        vitastor-0.6.15.el7.tar.gz

 BuildRequires:  liburing-devel >= 0.6
 BuildRequires:  gperftools-devel
--- a/rpm/vitastor-el8.Dockerfile
+++ b/rpm/vitastor-el8.Dockerfile
@@ -33,7 +33,7 @@ ADD . /root/vitastor
 RUN set -e; \
    cd /root/vitastor/rpm; \
    sh build-tarball.sh; \
-    cp /root/vitastor-0.6.12.el8.tar.gz ~/rpmbuild/SOURCES; \
+    cp /root/vitastor-0.6.15.el8.tar.gz ~/rpmbuild/SOURCES; \
    cp vitastor-el8.spec ~/rpmbuild/SPECS/vitastor.spec; \
    cd ~/rpmbuild/SPECS/; \
    rpmbuild -ba vitastor.spec; \
--- a/rpm/vitastor-el8.spec
+++ b/rpm/vitastor-el8.spec
@@ -1,11 +1,11 @@
 Name:           vitastor
-Version:        0.6.12
+Version:        0.6.15
 Release:        1%{?dist}
 Summary:        Vitastor, a fast software-defined clustered block storage

 License:        Vitastor Network Public License 1.1
 URL:            https://vitastor.io/
-Source0:        vitastor-0.6.12.el8.tar.gz
+Source0:        vitastor-0.6.15.el8.tar.gz

 BuildRequires:  liburing-devel >= 0.6
 BuildRequires:  gperftools-devel
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -15,7 +15,7 @@ if("${CMAKE_INSTALL_PREFIX}" MATCHES "^/usr/local/?$")
 	set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
 endif()

-add_definitions(-DVERSION="0.6.12")
+add_definitions(-DVERSION="0.6.15")
 add_definitions(-Wall -Wno-sign-compare -Wno-comment -Wno-parentheses -Wno-pointer-arith -fdiagnostics-color=always -I ${CMAKE_SOURCE_DIR}/src)
 if (${WITH_ASAN})
 	add_definitions(-fsanitize=address -fno-omit-frame-pointer)
@@ -155,7 +155,7 @@ target_link_libraries(vitastor-nbd
 # vitastor-cli
 add_executable(vitastor-cli
 	cli.cpp cli_alloc_osd.cpp cli_simple_offsets.cpp cli_df.cpp
-	cli_ls.cpp cli_create.cpp cli_modify.cpp cli_flatten.cpp cli_merge.cpp cli_rm.cpp cli_snap_rm.cpp
+	cli_ls.cpp cli_create.cpp cli_modify.cpp cli_flatten.cpp cli_merge.cpp cli_rm_data.cpp cli_rm.cpp
 )
 target_link_libraries(vitastor-cli
 	vitastor_client
--- a/src/addr_util.cpp
+++ b/src/addr_util.cpp
@@ -1,3 +1,5 @@
+#include <sys/socket.h>
+#include <unistd.h>
 #include <arpa/inet.h>
 #include <net/if.h>
 #include <sys/types.h>
@@ -9,7 +11,7 @@

 #include "addr_util.h"

-bool string_to_addr(std::string str, bool parse_port, int default_port, struct sockaddr *addr)
+bool string_to_addr(std::string str, bool parse_port, int default_port, struct sockaddr_storage *addr)
 {
    if (parse_port)
    {
@@ -25,7 +27,7 @@ bool string_to_addr(std::string str, bool parse_port, int default_port, struct s
    }
    if (inet_pton(AF_INET, str.c_str(), &((struct sockaddr_in*)addr)->sin_addr) == 1)
    {
-        addr->sa_family = AF_INET;
+        addr->ss_family = AF_INET;
        ((struct sockaddr_in*)addr)->sin_port = htons(default_port);
        return true;
    }
@@ -33,30 +35,30 @@ bool string_to_addr(std::string str, bool parse_port, int default_port, struct s
        str = str.substr(1, str.length()-2);
    if (inet_pton(AF_INET6, str.c_str(), &((struct sockaddr_in6*)addr)->sin6_addr) == 1)
    {
-        addr->sa_family = AF_INET6;
+        addr->ss_family = AF_INET6;
        ((struct sockaddr_in6*)addr)->sin6_port = htons(default_port);
        return true;
    }
    return false;
 }

-std::string addr_to_string(const sockaddr &addr)
+std::string addr_to_string(const sockaddr_storage &addr)
 {
    char peer_str[256];
    bool ok = false;
    int port;
-    if (addr.sa_family == AF_INET)
+    if (addr.ss_family == AF_INET)
    {
        ok = !!inet_ntop(AF_INET, &((sockaddr_in*)&addr)->sin_addr, peer_str, 256);
        port = ntohs(((sockaddr_in*)&addr)->sin_port);
    }
-    else if (addr.sa_family == AF_INET6)
+    else if (addr.ss_family == AF_INET6)
    {
        ok = !!inet_ntop(AF_INET6, &((sockaddr_in6*)&addr)->sin6_addr, peer_str, 256);
        port = ntohs(((sockaddr_in6*)&addr)->sin6_port);
    }
    else
-        throw std::runtime_error("Unknown address family "+std::to_string(addr.sa_family));
+        throw std::runtime_error("Unknown address family "+std::to_string(addr.ss_family));
    if (!ok)
        throw std::runtime_error(std::string("inet_ntop: ") + strerror(errno));
    return std::string(peer_str)+":"+std::to_string(port);
@@ -186,3 +188,51 @@ std::vector<std::string> getifaddr_list(std::vector<std::string> mask_cfg, bool
    freeifaddrs(list);
    return addresses;
 }
+
+int create_and_bind_socket(std::string bind_address, int bind_port, int listen_backlog, int *listening_port)
+{
+    sockaddr_storage addr;
+    if (!string_to_addr(bind_address, 0, bind_port, &addr))
+    {
+        throw std::runtime_error("bind address "+bind_address+" is not valid");
+    }
+
+    int listen_fd = socket(addr.ss_family, SOCK_STREAM, 0);
+    if (listen_fd < 0)
+    {
+        throw std::runtime_error(std::string("socket: ") + strerror(errno));
+    }
+    int enable = 1;
+    setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
+
+    if (bind(listen_fd, (sockaddr*)&addr, sizeof(addr)) < 0)
+    {
+        close(listen_fd);
+        throw std::runtime_error(std::string("bind: ") + strerror(errno));
+    }
+    if (listening_port)
+    {
+        if (bind_port == 0)
+        {
+            socklen_t len = sizeof(addr);
+            if (getsockname(listen_fd, (sockaddr *)&addr, &len) == -1)
+            {
+                close(listen_fd);
+                throw std::runtime_error(std::string("getsockname: ") + strerror(errno));
+            }
+            *listening_port = ntohs(((sockaddr_in*)&addr)->sin_port);
+        }
+        else
+        {
+            *listening_port = bind_port;
+        }
+    }
+
+    if (listen(listen_fd, listen_backlog ? listen_backlog : 128) < 0)
+    {
+        close(listen_fd);
+        throw std::runtime_error(std::string("listen: ") + strerror(errno));
+    }
+
+    return listen_fd;
+}
--- a/src/addr_util.h
+++ b/src/addr_util.h
@@ -4,6 +4,7 @@
 #include <string>
 #include <vector>

-bool string_to_addr(std::string str, bool parse_port, int default_port, struct sockaddr *addr);
-std::string addr_to_string(const sockaddr &addr);
+bool string_to_addr(std::string str, bool parse_port, int default_port, struct sockaddr_storage *addr);
+std::string addr_to_string(const sockaddr_storage &addr);
 std::vector<std::string> getifaddr_list(std::vector<std::string> mask_cfg = std::vector<std::string>(), bool include_v6 = false);
+int create_and_bind_socket(std::string bind_address, int bind_port, int listen_backlog, int *listening_port);
--- a/src/blockstore.h
+++ b/src/blockstore.h
@@ -21,7 +21,7 @@
 // Memory alignment for direct I/O (usually 512 bytes)
 // All other alignments must be a multiple of this one
 #ifndef MEM_ALIGNMENT
-#define MEM_ALIGNMENT 512
+#define MEM_ALIGNMENT 4096
 #endif

 // Default block size is 128 KB, current allowed range is 4K - 128M
--- a/src/blockstore_flush.cpp
+++ b/src/blockstore_flush.cpp
@@ -415,8 +415,11 @@ stop_flusher:
        flusher->active_flushers++;
 resume_1:
        // Find it in clean_db
-        clean_it = bs->clean_db.find(cur.oid);
-        old_clean_loc = (clean_it != bs->clean_db.end() ? clean_it->second.location : UINT64_MAX);
+        {
+            auto & clean_db = bs->clean_db_shard(cur.oid);
+            auto clean_it = clean_db.find(cur.oid);
+            old_clean_loc = (clean_it != clean_db.end() ? clean_it->second.location : UINT64_MAX);
+        }
        // Scan dirty versions of the object
        if (!scan_dirty(1))
        {
@@ -870,10 +873,11 @@ void journal_flusher_co::update_clean_db()
 #endif
        bs->data_alloc->set(old_clean_loc >> bs->block_order, false);
    }
+    auto & clean_db = bs->clean_db_shard(cur.oid);
    if (has_delete)
    {
-        auto clean_it = bs->clean_db.find(cur.oid);
-        bs->clean_db.erase(clean_it);
+        auto clean_it = clean_db.find(cur.oid);
+        clean_db.erase(clean_it);
 #ifdef BLOCKSTORE_DEBUG
        printf("Free block %lu from %lx:%lx v%lu (delete)\n",
            clean_loc >> bs->block_order,
@@ -884,7 +888,7 @@ void journal_flusher_co::update_clean_db()
    }
    else
    {
-        bs->clean_db[cur.oid] = {
+        clean_db[cur.oid] = {
            .version = cur.version,
            .location = clean_loc,
        };
--- a/src/blockstore_flush.h
+++ b/src/blockstore_flush.h
@@ -49,7 +49,6 @@ class journal_flusher_co
    std::function<void(ring_data_t*)> simple_callback_r, simple_callback_w;

    bool skip_copy, has_delete, has_writes;
-    blockstore_clean_db_t::iterator clean_it;
    std::vector<copy_buffer_t> v;
    std::vector<copy_buffer_t>::iterator it;
    int copy_count;
--- a/src/blockstore_impl.cpp
+++ b/src/blockstore_impl.cpp
@@ -118,7 +118,7 @@ void blockstore_impl_t::loop()
        // has_writes == 0 - no writes before the current queue item
        // has_writes == 1 - some writes in progress
        // has_writes == 2 - tried to submit some writes, but failed
-        int has_writes = 0, op_idx = 0, new_idx = 0;
+        int has_writes = 0, op_idx = 0, new_idx = 0, done_lists = 0;
        for (; op_idx < submit_queue.size(); op_idx++, new_idx++)
        {
            auto op = submit_queue[op_idx];
@@ -142,7 +142,6 @@ void blockstore_impl_t::loop()
                    continue;
                }
            }
-            unsigned ring_space = ringloop->space_left();
            unsigned prev_sqe_pos = ringloop->save();
            // 0 = can't submit
            // 1 = in progress
@@ -199,9 +198,14 @@ void blockstore_impl_t::loop()
            }
            else if (op->opcode == BS_OP_LIST)
            {
-                // LIST doesn't need to be blocked by previous modifications
-                process_list(op);
-                wr_st = 2;
+                // LIST doesn't have to be blocked by previous modifications
+                // But don't do a lot of LISTs at once, because they're blocking and potentially slow
+                if (single_tick_list_limit <= 0 || done_lists < single_tick_list_limit)
+                {
+                    process_list(op);
+                    done_lists++;
+                    wr_st = 2;
+                }
            }
            if (wr_st == 2)
            {
@@ -212,7 +216,6 @@ void blockstore_impl_t::loop()
                ringloop->restore(prev_sqe_pos);
                if (PRIV(op)->wait_for == WAIT_SQE)
                {
-                    PRIV(op)->wait_detail = 1 + ring_space;
                    // ring is full, stop submission
                    break;
                }
@@ -282,7 +285,7 @@ void blockstore_impl_t::check_wait(blockstore_op_t *op)
 {
    if (PRIV(op)->wait_for == WAIT_SQE)
    {
-        if (ringloop->space_left() < PRIV(op)->wait_detail)
+        if (ringloop->sqes_left() < PRIV(op)->wait_detail)
        {
            // stop submission if there's still no free space
 #ifdef BLOCKSTORE_DEBUG
@@ -425,22 +428,104 @@ static bool replace_stable(object_id oid, uint64_t version, int search_start, in
    return false;
 }

+blockstore_clean_db_t& blockstore_impl_t::clean_db_shard(object_id oid)
+{
+    uint64_t pg_num = 0;
+    uint64_t pool_id = (oid.inode >> (64-POOL_ID_BITS));
+    auto sh_it = clean_db_settings.find(pool_id);
+    if (sh_it != clean_db_settings.end())
+    {
+        // like map_to_pg()
+        pg_num = (oid.stripe / sh_it->second.pg_stripe_size) % sh_it->second.pg_count + 1;
+    }
+    return clean_db_shards[(pool_id << (64-POOL_ID_BITS)) | pg_num];
+}
+
+void blockstore_impl_t::reshard_clean_db(pool_id_t pool, uint32_t pg_count, uint32_t pg_stripe_size)
+{
+    uint64_t pool_id = (uint64_t)pool;
+    std::map<pool_pg_id_t, blockstore_clean_db_t> new_shards;
+    auto sh_it = clean_db_shards.lower_bound((pool_id << (64-POOL_ID_BITS)));
+    while (sh_it != clean_db_shards.end() &&
+        (sh_it->first >> (64-POOL_ID_BITS)) == pool_id)
+    {
+        for (auto & pair: sh_it->second)
+        {
+            // like map_to_pg()
+            uint64_t pg_num = (pair.first.stripe / pg_stripe_size) % pg_count + 1;
+            uint64_t shard_id = (pool_id << (64-POOL_ID_BITS)) | pg_num;
+            new_shards[shard_id][pair.first] = pair.second;
+        }
+        clean_db_shards.erase(sh_it++);
+    }
+    for (sh_it = new_shards.begin(); sh_it != new_shards.end(); sh_it++)
+    {
+        auto & to = clean_db_shards[sh_it->first];
+        to.swap(sh_it->second);
+    }
+    clean_db_settings[pool_id] = (pool_shard_settings_t){
+        .pg_count = pg_count,
+        .pg_stripe_size = pg_stripe_size,
+    };
+}
+
 void blockstore_impl_t::process_list(blockstore_op_t *op)
 {
-    uint32_t list_pg = op->offset;
+    uint32_t list_pg = op->offset+1;
    uint32_t pg_count = op->len;
    uint64_t pg_stripe_size = op->oid.stripe;
    uint64_t min_inode = op->oid.inode;
    uint64_t max_inode = op->version;
    // Check PG
-    if (pg_count != 0 && (pg_stripe_size < MIN_BLOCK_SIZE || list_pg >= pg_count))
+    if (pg_count != 0 && (pg_stripe_size < MIN_BLOCK_SIZE || list_pg > pg_count))
    {
        op->retval = -EINVAL;
        FINISH_OP(op);
        return;
    }
-    // Copy clean_db entries (sorted)
-    int stable_count = 0, stable_alloc = clean_db.size() / (pg_count ? pg_count : 1);
+    // Check if the DB needs resharding
+    // (we don't know about PGs from the beginning, we only create "shards" here)
+    uint64_t first_shard = 0, last_shard = UINT64_MAX;
+    if (min_inode != 0 &&
+        // Check if min_inode == max_inode == pool_id<<N, i.e. this is a pool listing
+        (min_inode >> (64-POOL_ID_BITS)) == (max_inode >> (64-POOL_ID_BITS)))
+    {
+        pool_id_t pool_id = (min_inode >> (64-POOL_ID_BITS));
+        if (pg_count > 1)
+        {
+            // Per-pg listing
+            auto sh_it = clean_db_settings.find(pool_id);
+            if (sh_it == clean_db_settings.end() ||
+                sh_it->second.pg_count != pg_count ||
+                sh_it->second.pg_stripe_size != pg_stripe_size)
+            {
+                reshard_clean_db(pool_id, pg_count, pg_stripe_size);
+            }
+            first_shard = last_shard = ((uint64_t)pool_id << (64-POOL_ID_BITS)) | list_pg;
+        }
+        else
+        {
+            // Per-pool listing
+            first_shard = ((uint64_t)pool_id << (64-POOL_ID_BITS));
+            last_shard = ((uint64_t)(pool_id+1) << (64-POOL_ID_BITS)) - 1;
+        }
+    }
+    // Copy clean_db entries
+    int stable_count = 0, stable_alloc = 0;
+    if (min_inode != max_inode)
+    {
+        for (auto shard_it = clean_db_shards.lower_bound(first_shard);
+            shard_it != clean_db_shards.end() && shard_it->first <= last_shard;
+            shard_it++)
+        {
+            auto & clean_db = shard_it->second;
+            stable_alloc += clean_db.size();
+        }
+    }
+    else
+    {
+        stable_alloc = 32768;
+    }
    obj_ver_id *stable = (obj_ver_id*)malloc(sizeof(obj_ver_id) * stable_alloc);
    if (!stable)
    {
@@ -448,7 +533,11 @@ void blockstore_impl_t::process_list(blockstore_op_t *op)
        FINISH_OP(op);
        return;
    }
+    for (auto shard_it = clean_db_shards.lower_bound(first_shard);
+        shard_it != clean_db_shards.end() && shard_it->first <= last_shard;
+        shard_it++)
    {
+        auto & clean_db = shard_it->second;
        auto clean_it = clean_db.begin(), clean_end = clean_db.end();
        if ((min_inode != 0 || max_inode != 0) && min_inode <= max_inode)
        {
@@ -463,26 +552,28 @@ void blockstore_impl_t::process_list(blockstore_op_t *op)
        }
        for (; clean_it != clean_end; clean_it++)
        {
-            if (!pg_count || ((clean_it->first.stripe / pg_stripe_size) % pg_count) == list_pg) // like map_to_pg()
+            if (stable_count >= stable_alloc)
            {
-                if (stable_count >= stable_alloc)
+                stable_alloc *= 2;
+                stable = (obj_ver_id*)realloc(stable, sizeof(obj_ver_id) * stable_alloc);
+                if (!stable)
                {
-                    stable_alloc += 32768;
-                    stable = (obj_ver_id*)realloc(stable, sizeof(obj_ver_id) * stable_alloc);
-                    if (!stable)
-                    {
-                        op->retval = -ENOMEM;
-                        FINISH_OP(op);
-                        return;
-                    }
+                    op->retval = -ENOMEM;
+                    FINISH_OP(op);
+                    return;
                }
-                stable[stable_count++] = {
-                    .oid = clean_it->first,
-                    .version = clean_it->second.version,
-                };
            }
+            stable[stable_count++] = {
+                .oid = clean_it->first,
+                .version = clean_it->second.version,
+            };
        }
    }
+    if (first_shard != last_shard)
+    {
+        // If that's not a per-PG listing, sort clean entries
+        std::sort(stable, stable+stable_count);
+    }
    int clean_stable_count = stable_count;
    // Copy dirty_db entries (sorted, too)
    int unstable_count = 0, unstable_alloc = 0;
@@ -508,7 +599,7 @@ void blockstore_impl_t::process_list(blockstore_op_t *op)
        }
        for (; dirty_it != dirty_end; dirty_it++)
        {
-            if (!pg_count || ((dirty_it->first.oid.stripe / pg_stripe_size) % pg_count) == list_pg) // like map_to_pg()
+            if (!pg_count || ((dirty_it->first.oid.stripe / pg_stripe_size) % pg_count + 1) == list_pg) // like map_to_pg()
            {
                if (IS_DELETE(dirty_it->second.state))
                {
--- a/src/blockstore_impl.h
+++ b/src/blockstore_impl.h
@@ -55,9 +55,10 @@
 #define IS_DELETE(st) (((st) & 0x0F) == BS_ST_DELETE)

 #define BS_SUBMIT_CHECK_SQES(n) \
-    if (ringloop->space_left() < (n))\
+    if (ringloop->sqes_left() < (n))\
    {\
        /* Pause until there are more requests available */\
+        PRIV(op)->wait_detail = (n);\
        PRIV(op)->wait_for = WAIT_SQE;\
        return 0;\
    }
@@ -71,6 +72,7 @@
    if (!sqe)\
    {\
        /* Pause until there are more requests available */\
+        PRIV(op)->wait_detail = 1;\
        PRIV(op)->wait_for = WAIT_SQE;\
        return 0;\
    }
@@ -80,6 +82,7 @@
    if (!sqe)\
    {\
        /* Pause until there are more requests available */\
+        PRIV(op)->wait_detail = 1;\
        PRIV(op)->wait_for = WAIT_SQE;\
        return 0;\
    }
@@ -201,6 +204,17 @@ typedef std::map<obj_ver_id, dirty_entry> blockstore_dirty_db_t;

 #include "blockstore_flush.h"

+typedef uint32_t pool_id_t;
+typedef uint64_t pool_pg_id_t;
+
+#define POOL_ID_BITS 16
+
+struct pool_shard_settings_t
+{
+    uint32_t pg_count;
+    uint32_t pg_stripe_size;
+};
+
 class blockstore_impl_t
 {
    /******* OPTIONS *******/
@@ -238,11 +252,14 @@ class blockstore_impl_t
    int throttle_target_parallelism = 1;
    // Minimum difference in microseconds between target and real execution times to throttle the response
    int throttle_threshold_us = 50;
+    // Maximum number of LIST operations to be processed between
+    int single_tick_list_limit = 1;
    /******* END OF OPTIONS *******/

    struct ring_consumer_t ring_consumer;

-    blockstore_clean_db_t clean_db;
+    std::map<pool_id_t, pool_shard_settings_t> clean_db_settings;
+    std::map<pool_pg_id_t, blockstore_clean_db_t> clean_db_shards;
    uint8_t *clean_bitmap = NULL;
    blockstore_dirty_db_t dirty_db;
    std::vector<blockstore_op_t*> submit_queue;
@@ -291,6 +308,9 @@ class blockstore_impl_t
    void open_journal();
    uint8_t* get_clean_entry_bitmap(uint64_t block_loc, int offset);

+    blockstore_clean_db_t& clean_db_shard(object_id oid);
+    void reshard_clean_db(pool_id_t pool_id, uint32_t pg_count, uint32_t pg_stripe_size);
+
    // Journaling
    void prepare_journal_sector_write(int sector, blockstore_op_t *op);
    void handle_journal_write(ring_data_t *data, uint64_t flush_id);
--- a/src/blockstore_init.cpp
+++ b/src/blockstore_init.cpp
@@ -222,10 +222,11 @@ void blockstore_init_meta::handle_entries(void* entries, unsigned count, int blo
        }
        if (entry->oid.inode > 0)
        {
-            auto clean_it = bs->clean_db.find(entry->oid);
-            if (clean_it == bs->clean_db.end() || clean_it->second.version < entry->version)
+            auto & clean_db = bs->clean_db_shard(entry->oid);
+            auto clean_it = clean_db.find(entry->oid);
+            if (clean_it == clean_db.end() || clean_it->second.version < entry->version)
            {
-                if (clean_it != bs->clean_db.end())
+                if (clean_it != clean_db.end())
                {
                    // free the previous block
 #ifdef BLOCKSTORE_DEBUG
@@ -245,7 +246,7 @@ void blockstore_init_meta::handle_entries(void* entries, unsigned count, int blo
                printf("Allocate block (clean entry) %lu: %lx:%lx v%lu\n", done_cnt+i, entry->oid.inode, entry->oid.stripe, entry->version);
 #endif
                bs->data_alloc->set(done_cnt+i, true);
-                bs->clean_db[entry->oid] = (struct clean_entry){
+                clean_db[entry->oid] = (struct clean_entry){
                    .version = entry->version,
                    .location = (done_cnt+i) << block_order,
                };
@@ -656,8 +657,9 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                    init_write_sector = proc_pos;
                    return 0;
                }
-                auto clean_it = bs->clean_db.find(je->small_write.oid);
-                if (clean_it == bs->clean_db.end() ||
+                auto & clean_db = bs->clean_db_shard(je->small_write.oid);
+                auto clean_it = clean_db.find(je->small_write.oid);
+                if (clean_it == clean_db.end() ||
                    clean_it->second.version < je->small_write.version)
                {
                    obj_ver_id ov = {
@@ -735,8 +737,9 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                        erase_dirty_object(dirty_it);
                    }
                }
-                auto clean_it = bs->clean_db.find(je->big_write.oid);
-                if (clean_it == bs->clean_db.end() ||
+                auto & clean_db = bs->clean_db_shard(je->big_write.oid);
+                auto clean_it = clean_db.find(je->big_write.oid);
+                if (clean_it == clean_db.end() ||
                    clean_it->second.version < je->big_write.version)
                {
                    // oid, version, block
@@ -841,8 +844,9 @@ int blockstore_init_journal::handle_journal_part(void *buf, uint64_t done_pos, u
                    dirty_it--;
                    dirty_exists = dirty_it->first.oid == je->del.oid;
                }
-                auto clean_it = bs->clean_db.find(je->del.oid);
-                bool clean_exists = (clean_it != bs->clean_db.end() &&
+                auto & clean_db = bs->clean_db_shard(je->del.oid);
+                auto clean_it = clean_db.find(je->del.oid);
+                bool clean_exists = (clean_it != clean_db.end() &&
                    clean_it->second.version < je->del.version);
                if (!clean_exists && dirty_exists)
                {
@@ -901,8 +905,9 @@ void blockstore_init_journal::erase_dirty_object(blockstore_dirty_db_t::iterator
            break;
        }
    }
-    auto clean_it = bs->clean_db.find(oid);
-    uint64_t clean_loc = clean_it != bs->clean_db.end()
+    auto & clean_db = bs->clean_db_shard(oid);
+    auto clean_it = clean_db.find(oid);
+    uint64_t clean_loc = clean_it != clean_db.end()
        ? clean_it->second.location : UINT64_MAX;
    if (exists && clean_loc == UINT64_MAX)
    {
--- a/src/blockstore_read.cpp
+++ b/src/blockstore_read.cpp
@@ -111,6 +111,7 @@ uint8_t* blockstore_impl_t::get_clean_entry_bitmap(uint64_t block_loc, int offse

 int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
 {
+    auto & clean_db = clean_db_shard(read_op->oid);
    auto clean_it = clean_db.find(read_op->oid);
    auto dirty_it = dirty_db.upper_bound((obj_ver_id){
        .oid = read_op->oid,
@@ -297,6 +298,7 @@ int blockstore_impl_t::read_bitmap(object_id oid, uint64_t target_version, void
            dirty_it--;
        }
    }
+    auto & clean_db = clean_db_shard(oid);
    auto clean_it = clean_db.find(oid);
    if (clean_it != clean_db.end())
    {
--- a/src/blockstore_stable.cpp
+++ b/src/blockstore_stable.cpp
@@ -54,6 +54,7 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
        auto dirty_it = dirty_db.find(*v);
        if (dirty_it == dirty_db.end())
        {
+            auto & clean_db = clean_db_shard(v->oid);
            auto clean_it = clean_db.find(v->oid);
            if (clean_it == clean_db.end() || clean_it->second.version < v->version)
            {
@@ -188,6 +189,7 @@ void blockstore_impl_t::mark_stable(const obj_ver_id & v, bool forget_dirty)
                    }
                    if (exists == -1)
                    {
+                        auto & clean_db = clean_db_shard(v.oid);
                        auto clean_it = clean_db.find(v.oid);
                        exists = clean_it != clean_db.end() ? 1 : 0;
                    }
@@ -215,6 +217,7 @@ void blockstore_impl_t::mark_stable(const obj_ver_id & v, bool forget_dirty)
                        break;
                    }
                }
+                auto & clean_db = clean_db_shard(v.oid);
                auto clean_it = clean_db.find(v.oid);
                uint64_t clean_loc = clean_it != clean_db.end()
                    ? clean_it->second.location : UINT64_MAX;
--- a/src/blockstore_write.cpp
+++ b/src/blockstore_write.cpp
@@ -41,6 +41,7 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
    }
    if (!found)
    {
+        auto & clean_db = clean_db_shard(op->oid);
        auto clean_it = clean_db.find(op->oid);
        if (clean_it != clean_db.end())
        {
--- a/src/cli.cpp
+++ b/src/cli.cpp
@@ -365,6 +365,13 @@ void cli_tool_t::run(json11::Json cfg)
        if (action_cb != NULL)
            ringloop->wait();
    }
+    // Destroy the client
+    delete cli;
+    delete epmgr;
+    delete ringloop;
+    cli = NULL;
+    epmgr = NULL;
+    ringloop = NULL;
 }

 int main(int narg, const char *args[])
@@ -374,5 +381,6 @@ int main(int narg, const char *args[])
    exe_name = args[0];
    cli_tool_t *p = new cli_tool_t();
    p->run(cli_tool_t::parse_args(narg, args));
+    delete p;
    return 0;
 }
--- a/src/cli_df.cpp
+++ b/src/cli_df.cpp
@@ -108,9 +108,14 @@ resume_1:
                    pool_avail = pg_free;
                }
            }
+            if (pool_avail == UINT64_MAX)
+            {
+                pool_avail = 0;
+            }
            if (pool_cfg.scheme != POOL_SCHEME_REPLICATED)
            {
-                pool_avail = pool_avail * (pool_cfg.pg_size - pool_cfg.parity_chunks) / pool_stats[pool_cfg.id]["pg_real_size"].uint64_value();
+                uint64_t pg_real_size = pool_stats[pool_cfg.id]["pg_real_size"].uint64_value();
+                pool_avail = pg_real_size > 0 ? pool_avail * (pool_cfg.pg_size - pool_cfg.parity_chunks) / pg_real_size : 0;
            }
            pool_stats[pool_cfg.id] = json11::Json::object {
                { "name", pool_cfg.name },
@@ -189,11 +194,16 @@ resume_1:
        json11::Json::array list;
        for (auto & kv: pool_stats)
        {
-            kv.second["total_fmt"] = format_size(kv.second["total_raw"].uint64_value() / kv.second["raw_to_usable"].number_value());
-            kv.second["used_fmt"] = format_size(kv.second["used_raw"].uint64_value() / kv.second["raw_to_usable"].number_value());
+            double raw_to = kv.second["raw_to_usable"].number_value();
+            if (raw_to < 0.000001 && raw_to > -0.000001)
+                raw_to = 1;
+            kv.second["total_fmt"] = format_size(kv.second["total_raw"].uint64_value() / raw_to);
+            kv.second["used_fmt"] = format_size(kv.second["used_raw"].uint64_value() / raw_to);
            kv.second["max_avail_fmt"] = format_size(kv.second["max_available"].uint64_value());
-            kv.second["used_pct"] = format_q(100 - 100*kv.second["max_available"].uint64_value() *
-                kv.second["raw_to_usable"].number_value() / kv.second["total_raw"].uint64_value())+"%";
+            kv.second["used_pct"] = format_q(kv.second["total_raw"].uint64_value()
+                ? (100 - 100*kv.second["max_available"].uint64_value() *
+                    kv.second["raw_to_usable"].number_value() / kv.second["total_raw"].uint64_value())
+                : 100)+"%";
            kv.second["eff_fmt"] = format_q(kv.second["space_efficiency"].number_value()*100)+"%";
        }
        printf("%s", print_table(to_list(), cols, parent->color).c_str());
--- a/src/cli_ls.cpp
+++ b/src/cli_ls.cpp
@@ -154,7 +154,7 @@ resume_1:
            if (pool_it != parent->cli->st_cli.pool_config.end())
            {
                auto & pool_cfg = pool_it->second;
-                used_size = used_size / pool_pg_real_size[pool_id]
+                used_size = used_size / (pool_pg_real_size[pool_id] ? pool_pg_real_size[pool_id] : 1)
                    * (pool_cfg.scheme == POOL_SCHEME_REPLICATED ? 1 : pool_cfg.pg_size-pool_cfg.parity_chunks);
            }
            auto stat_it = stats.find(inode_num);
--- a/src/cli_rm.cpp
+++ b/src/cli_rm.cpp
@@ -1,211 +1,566 @@
 // Copyright (c) Vitaliy Filippov, 2019+
 // License: VNPL-1.1 (see README.md for details)

+#include <fcntl.h>
 #include "cli.h"
 #include "cluster_client.h"
+#include "base64.h"

-#define RM_LISTING 1
-#define RM_REMOVING 2
-#define RM_END 3
-
-struct rm_pg_t
+// Remove layer(s): similar to merge, but alters metadata and processes multiple merge targets
+//
+// Exactly one child of the requested layers may be merged using the "inverted" workflow,
+// where we merge it "down" into one of the "to-be-removed" layers and then rename the
+// "to-be-removed" layer to the child. It may be done either if all writers are stopped
+// before trying to delete layers (which is signaled by --writers-stopped) or if that child
+// is a read-only layer (snapshot) itself.
+//
+// This "inverted" workflow trades copying data of one of the deleted layers for copying
+// data of one child of the chain which is also a child of the "traded" layer. So we
+// choose the (parent,child) pair which has the largest difference between "parent" and
+// "child" inode sizes.
+//
+// All other children of the chain are processed by iterating though them, merging removed
+// parents into them and rebasing them to the last layer which isn't a member of the removed
+// chain.
+//
+// Example:
+//
+// <parent> - <from> - <layer 2> - <to> - <child 1>
+//                 \           \       \- <child 2>
+//                  \           \- <child 3>
+//                   \-<child 4>
+//
+// 1) Find optimal pair for the "reverse" scenario
+//    Imagine that it's (<layer 2>, <child 1>) in this example
+// 2) Process all children except <child 1>:
+//    - Merge <from>..<to> to <child 2>
+//    - Set <child 2> parent to <parent>
+//    - Repeat for others
+// 3) Process <child 1>:
+//    - Merge <from>..<child 1> to <layer 2>
+//    - Set <layer 2> parent to <parent>
+//    - Rename <layer 2> to <child 1>
+// 4) Delete other layers of the chain (<from>, <to>)
+struct snap_remover_t
 {
-    pg_num_t pg_num;
-    osd_num_t rm_osd_num;
-    std::set<object_id> objects;
-    std::set<object_id>::iterator obj_pos;
-    uint64_t obj_count = 0, obj_done = 0;
+    cli_tool_t *parent;
+
+    // remove from..to
+    std::string from_name, to_name;
+    // writers are stopped, we can safely change writable layers
+    bool writers_stopped = false;
+    // use CAS writes (0 = never, 1 = auto, 2 = always)
+    int use_cas = 1;
+    // interval between fsyncs
+    int fsync_interval = 128;
+
+    std::map<inode_t,int> sources;
+    std::map<inode_t,uint64_t> inode_used;
+    std::vector<inode_t> merge_children;
+    std::vector<inode_t> chain_list;
+    std::map<inode_t,int> inverse_candidates;
+    inode_t inverse_parent = 0, inverse_child = 0;
+    inode_t new_parent = 0;
    int state = 0;
-    int in_flight = 0;
-};
+    int current_child = 0;
+    std::function<bool(void)> cb;

-struct rm_inode_t
-{
-    uint64_t inode = 0;
-    pool_id_t pool_id = 0;
-    uint64_t min_offset = 0;
-
-    cli_tool_t *parent = NULL;
-    inode_list_t *lister = NULL;
-    std::vector<rm_pg_t*> lists;
-    uint64_t total_count = 0, total_done = 0, total_prev_pct = 0;
-    uint64_t pgs_to_list = 0;
-    bool lists_done = false;
-    int state = 0;
-
-    void start_delete()
+    bool is_done()
    {
-        lister = parent->cli->list_inode_start(inode, [this](inode_list_t *lst,
-            std::set<object_id>&& objects, pg_num_t pg_num, osd_num_t primary_osd, int status)
+        return state == 9;
+    }
+
+    void loop()
+    {
+        if (state == 1)
+            goto resume_1;
+        else if (state == 2)
+            goto resume_2;
+        else if (state == 3)
+            goto resume_3;
+        else if (state == 4)
+            goto resume_4;
+        else if (state == 5)
+            goto resume_5;
+        else if (state == 6)
+            goto resume_6;
+        else if (state == 7)
+            goto resume_7;
+        else if (state == 8)
+            goto resume_8;
+        else if (state == 9)
+            goto resume_9;
+        // Get children to merge
+        get_merge_children();
+        // Try to select an inode for the "inverse" optimized scenario
+        // Read statistics from etcd to do it
+        read_stats();
+        state = 1;
+resume_1:
+        if (parent->waiting > 0)
+            return;
+        choose_inverse_candidate();
+        // Merge children one by one, except our "inverse" child
+        for (current_child = 0; current_child < merge_children.size(); current_child++)
        {
-            rm_pg_t *rm = new rm_pg_t((rm_pg_t){
-                .pg_num = pg_num,
-                .rm_osd_num = primary_osd,
-                .objects = objects,
-                .obj_count = objects.size(),
-                .obj_done = 0,
-            });
-            if (min_offset == 0)
+            if (merge_children[current_child] == inverse_child)
+                continue;
+            start_merge_child(merge_children[current_child], merge_children[current_child]);
+resume_2:
+            while (!cb())
            {
-                total_count += objects.size();
+                state = 2;
+                return;
            }
-            else
-            {
-                for (object_id oid: objects)
-                {
-                    if (oid.stripe >= min_offset)
-                    {
-                        total_count++;
-                    }
-                }
-            }
-            rm->obj_pos = rm->objects.begin();
-            lists.push_back(rm);
-            if (parent->list_first)
-            {
-                parent->cli->list_inode_next(lister, 1);
-            }
-            if (status & INODE_LIST_DONE)
-            {
-                lists_done = true;
-            }
-            pgs_to_list--;
-            continue_delete();
-        });
-        if (!lister)
+            cb = NULL;
+            parent->change_parent(merge_children[current_child], new_parent);
+            state = 3;
+resume_3:
+            if (parent->waiting > 0)
+                return;
+        }
+        // Merge our "inverse" child into our "inverse" parent
+        if (inverse_child != 0)
        {
-            fprintf(stderr, "Failed to list inode %lu from pool %u objects\n", INODE_NO_POOL(inode), INODE_POOL(inode));
+            start_merge_child(inverse_child, inverse_parent);
+resume_4:
+            while (!cb())
+            {
+                state = 4;
+                return;
+            }
+            cb = NULL;
+            // Delete "inverse" child data
+            start_delete_source(inverse_child);
+resume_5:
+            while (!cb())
+            {
+                state = 5;
+                return;
+            }
+            cb = NULL;
+            // Delete "inverse" child metadata, rename parent over it,
+            // and also change parent links of the previous "inverse" child
+            rename_inverse_parent();
+            state = 6;
+resume_6:
+            if (parent->waiting > 0)
+                return;
+        }
+        // Delete parents, except the "inverse" one
+        for (current_child = 0; current_child < chain_list.size(); current_child++)
+        {
+            if (chain_list[current_child] == inverse_parent)
+                continue;
+            start_delete_source(chain_list[current_child]);
+resume_7:
+            while (!cb())
+            {
+                state = 7;
+                return;
+            }
+            cb = NULL;
+            delete_inode_config(chain_list[current_child]);
+            state = 8;
+resume_8:
+            if (parent->waiting > 0)
+                return;
+        }
+        state = 9;
+resume_9:
+        // Done
+        return;
+    }
+
+    void get_merge_children()
+    {
+        // Get all children of from..to
+        inode_config_t *from_cfg = parent->get_inode_cfg(from_name);
+        inode_config_t *to_cfg = parent->get_inode_cfg(to_name);
+        // Check that to_cfg is actually a child of from_cfg
+        // FIXME de-copypaste the following piece of code with snap_merger_t
+        inode_config_t *cur = to_cfg;
+        chain_list.push_back(cur->num);
+        while (cur->num != from_cfg->num && cur->parent_id != 0)
+        {
+            auto it = parent->cli->st_cli.inode_config.find(cur->parent_id);
+            if (it == parent->cli->st_cli.inode_config.end())
+            {
+                fprintf(stderr, "Parent inode of layer %s (id %ld) not found\n", cur->name.c_str(), cur->parent_id);
+                exit(1);
+            }
+            cur = &it->second;
+            chain_list.push_back(cur->num);
+        }
+        if (cur->num != from_cfg->num)
+        {
+            fprintf(stderr, "Layer %s is not a child of %s\n", to_name.c_str(), from_name.c_str());
            exit(1);
        }
-        pgs_to_list = parent->cli->list_pg_count(lister);
-        parent->cli->list_inode_next(lister, parent->parallel_osds);
-    }
-
-    void send_ops(rm_pg_t *cur_list)
-    {
-        if (parent->cli->msgr.osd_peer_fds.find(cur_list->rm_osd_num) ==
-            parent->cli->msgr.osd_peer_fds.end())
+        new_parent = from_cfg->parent_id;
+        // Calculate ranks
+        int i = chain_list.size()-1;
+        for (inode_t item: chain_list)
        {
-            // Initiate connection
-            parent->cli->msgr.connect_peer(cur_list->rm_osd_num, parent->cli->st_cli.peer_states[cur_list->rm_osd_num]);
-            return;
+            sources[item] = i--;
        }
-        while (cur_list->in_flight < parent->iodepth && cur_list->obj_pos != cur_list->objects.end())
+        for (auto & ic: parent->cli->st_cli.inode_config)
        {
-            if (cur_list->obj_pos->stripe >= min_offset)
+            if (!ic.second.parent_id)
            {
-                osd_op_t *op = new osd_op_t();
-                op->op_type = OSD_OP_OUT;
-                op->peer_fd = parent->cli->msgr.osd_peer_fds[cur_list->rm_osd_num];
-                op->req = (osd_any_op_t){
-                    .rw = {
-                        .header = {
-                            .magic = SECONDARY_OSD_OP_MAGIC,
-                            .id = parent->cli->next_op_id(),
-                            .opcode = OSD_OP_DELETE,
-                        },
-                        .inode = cur_list->obj_pos->inode,
-                        .offset = cur_list->obj_pos->stripe,
-                        .len = 0,
-                    },
-                };
-                op->callback = [this, cur_list](osd_op_t *op)
-                {
-                    cur_list->in_flight--;
-                    if (op->reply.hdr.retval < 0)
-                    {
-                        fprintf(stderr, "Failed to remove object %lx:%lx from PG %u (OSD %lu) (retval=%ld)\n",
-                            op->req.rw.inode, op->req.rw.offset,
-                            cur_list->pg_num, cur_list->rm_osd_num, op->reply.hdr.retval);
-                    }
-                    delete op;
-                    cur_list->obj_done++;
-                    total_done++;
-                    continue_delete();
-                };
-                cur_list->in_flight++;
-                parent->cli->msgr.outbox_push(op);
+                continue;
            }
-            cur_list->obj_pos++;
-        }
-    }
-
-    void continue_delete()
-    {
-        if (parent->list_first && !lists_done)
-        {
-            return;
-        }
-        for (int i = 0; i < lists.size(); i++)
-        {
-            if (!lists[i]->in_flight && lists[i]->obj_pos == lists[i]->objects.end())
+            auto it = sources.find(ic.second.parent_id);
+            if (it != sources.end() && sources.find(ic.second.num) == sources.end())
            {
-                delete lists[i];
-                lists.erase(lists.begin()+i, lists.begin()+i+1);
-                i--;
-                if (!lists_done)
+                merge_children.push_back(ic.second.num);
+                if (ic.second.readonly || writers_stopped)
                {
-                    parent->cli->list_inode_next(lister, 1);
+                    inverse_candidates[ic.second.num] = it->second;
                }
            }
-            else
-            {
-                send_ops(lists[i]);
-            }
-        }
-        if (parent->progress && total_count > 0 && total_done*1000/total_count != total_prev_pct)
-        {
-            printf("\rRemoved %lu/%lu objects, %lu more PGs to list...", total_done, total_count, pgs_to_list);
-            total_prev_pct = total_done*1000/total_count;
-        }
-        if (lists_done && !lists.size())
-        {
-            printf("Done, inode %lu in pool %u data removed\n", INODE_NO_POOL(inode), pool_id);
-            state = 2;
        }
    }

-    bool loop()
+    void read_stats()
    {
-        if (state == 0)
+        if (inverse_candidates.size() == 0)
        {
-            start_delete();
-            state = 1;
+            return;
        }
-        else if (state == 1)
+        json11::Json::array reads;
+        for (auto cp: inverse_candidates)
        {
-            continue_delete();
+            inode_t inode = cp.first;
+            reads.push_back(json11::Json::object {
+                { "request_range", json11::Json::object {
+                    { "key", base64_encode(
+                        parent->cli->st_cli.etcd_prefix+
+                        "/inode/stats/"+std::to_string(INODE_POOL(inode))+
+                        "/"+std::to_string(INODE_NO_POOL(inode))
+                    ) },
+                } }
+            });
        }
-        else if (state == 2)
+        for (auto cp: sources)
        {
-            return true;
+            inode_t inode = cp.first;
+            reads.push_back(json11::Json::object {
+                { "request_range", json11::Json::object {
+                    { "key", base64_encode(
+                        parent->cli->st_cli.etcd_prefix+
+                        "/inode/stats/"+std::to_string(INODE_POOL(inode))+
+                        "/"+std::to_string(INODE_NO_POOL(inode))
+                    ) },
+                } }
+            });
        }
-        return false;
+        parent->waiting++;
+        parent->cli->st_cli.etcd_txn_slow(json11::Json::object {
+            { "success", reads },
+        }, [this](std::string err, json11::Json data)
+        {
+            parent->waiting--;
+            if (err != "")
+            {
+                fprintf(stderr, "Error reading layer statistics from etcd: %s\n", err.c_str());
+                exit(1);
+            }
+            for (auto inode_result: data["responses"].array_items())
+            {
+                auto kv = parent->cli->st_cli.parse_etcd_kv(inode_result["kvs"][0]);
+                pool_id_t pool_id = 0;
+                inode_t inode = 0;
+                char null_byte = 0;
+                sscanf(kv.key.c_str() + parent->cli->st_cli.etcd_prefix.length()+13, "%u/%lu%c", &pool_id, &inode, &null_byte);
+                if (!inode || null_byte != 0)
+                {
+                    fprintf(stderr, "Bad key returned from etcd: %s\n", kv.key.c_str());
+                    exit(1);
+                }
+                auto pool_cfg_it = parent->cli->st_cli.pool_config.find(pool_id);
+                if (pool_cfg_it == parent->cli->st_cli.pool_config.end())
+                {
+                    fprintf(stderr, "Pool %u does not exist\n", pool_id);
+                    exit(1);
+                }
+                inode = INODE_WITH_POOL(pool_id, inode);
+                auto & pool_cfg = pool_cfg_it->second;
+                uint64_t used_bytes = kv.value["raw_used"].uint64_value() / pool_cfg.pg_size;
+                if (pool_cfg.scheme != POOL_SCHEME_REPLICATED)
+                {
+                    used_bytes *= (pool_cfg.pg_size - pool_cfg.parity_chunks);
+                }
+                inode_used[inode] = used_bytes;
+            }
+            parent->ringloop->wakeup();
+        });
+    }
+
+    void choose_inverse_candidate()
+    {
+        uint64_t max_diff = 0;
+        for (auto cp: inverse_candidates)
+        {
+            inode_t child = cp.first;
+            uint64_t child_used = inode_used[child];
+            int rank = cp.second;
+            for (int i = chain_list.size()-rank; i < chain_list.size(); i++)
+            {
+                inode_t parent = chain_list[i];
+                uint64_t parent_used = inode_used[parent];
+                if (parent_used > child_used && (!max_diff || max_diff < (parent_used-child_used)))
+                {
+                    max_diff = (parent_used-child_used);
+                    inverse_parent = parent;
+                    inverse_child = child;
+                }
+            }
+        }
+    }
+
+    void rename_inverse_parent()
+    {
+        auto child_it = parent->cli->st_cli.inode_config.find(inverse_child);
+        if (child_it == parent->cli->st_cli.inode_config.end())
+        {
+            fprintf(stderr, "Inode %ld disappeared\n", inverse_child);
+            exit(1);
+        }
+        auto target_it = parent->cli->st_cli.inode_config.find(inverse_parent);
+        if (target_it == parent->cli->st_cli.inode_config.end())
+        {
+            fprintf(stderr, "Inode %ld disappeared\n", inverse_parent);
+            exit(1);
+        }
+        inode_config_t *child_cfg = &child_it->second;
+        inode_config_t *target_cfg = &target_it->second;
+        std::string child_name = child_cfg->name;
+        std::string target_name = target_cfg->name;
+        std::string child_cfg_key = base64_encode(
+            parent->cli->st_cli.etcd_prefix+
+            "/config/inode/"+std::to_string(INODE_POOL(inverse_child))+
+            "/"+std::to_string(INODE_NO_POOL(inverse_child))
+        );
+        std::string target_cfg_key = base64_encode(
+            parent->cli->st_cli.etcd_prefix+
+            "/config/inode/"+std::to_string(INODE_POOL(inverse_parent))+
+            "/"+std::to_string(INODE_NO_POOL(inverse_parent))
+        );
+        // Fill new configuration
+        inode_config_t new_cfg = *child_cfg;
+        new_cfg.num = target_cfg->num;
+        new_cfg.parent_id = new_parent;
+        json11::Json::array cmp = json11::Json::array {
+            json11::Json::object {
+                { "target", "MOD" },
+                { "key", child_cfg_key },
+                { "result", "LESS" },
+                { "mod_revision", child_cfg->mod_revision+1 },
+            },
+            json11::Json::object {
+                { "target", "MOD" },
+                { "key", target_cfg_key },
+                { "result", "LESS" },
+                { "mod_revision", target_cfg->mod_revision+1 },
+            },
+        };
+        json11::Json::array txn = json11::Json::array {
+            json11::Json::object {
+                { "request_delete_range", json11::Json::object {
+                    { "key", child_cfg_key },
+                } },
+            },
+            json11::Json::object {
+                { "request_put", json11::Json::object {
+                    { "key", target_cfg_key },
+                    { "value", base64_encode(json11::Json(parent->cli->st_cli.serialize_inode_cfg(&new_cfg)).dump()) },
+                } },
+            },
+            json11::Json::object {
+                { "request_put", json11::Json::object {
+                    { "key", base64_encode(parent->cli->st_cli.etcd_prefix+"/index/image/"+child_cfg->name) },
+                    { "value", base64_encode(json11::Json({
+                        { "id", INODE_NO_POOL(inverse_parent) },
+                        { "pool_id", (uint64_t)INODE_POOL(inverse_parent) },
+                    }).dump()) },
+                } },
+            },
+        };
+        // Reparent children of inverse_child
+        for (auto & cp: parent->cli->st_cli.inode_config)
+        {
+            if (cp.second.parent_id == child_cfg->num)
+            {
+                auto cp_cfg = cp.second;
+                cp_cfg.parent_id = inverse_parent;
+                auto cp_key = base64_encode(
+                    parent->cli->st_cli.etcd_prefix+
+                    "/config/inode/"+std::to_string(INODE_POOL(cp.second.num))+
+                    "/"+std::to_string(INODE_NO_POOL(cp.second.num))
+                );
+                cmp.push_back(json11::Json::object {
+                    { "target", "MOD" },
+                    { "key", cp_key },
+                    { "result", "LESS" },
+                    { "mod_revision", cp.second.mod_revision+1 },
+                });
+                txn.push_back(json11::Json::object {
+                    { "request_put", json11::Json::object {
+                        { "key", cp_key },
+                        { "value", base64_encode(json11::Json(parent->cli->st_cli.serialize_inode_cfg(&cp_cfg)).dump()) },
+                    } },
+                });
+            }
+        }
+        parent->waiting++;
+        parent->cli->st_cli.etcd_txn_slow(json11::Json::object {
+            { "compare", cmp },
+            { "success", txn },
+        }, [this, target_name, child_name](std::string err, json11::Json res)
+        {
+            parent->waiting--;
+            if (err != "")
+            {
+                fprintf(stderr, "Error renaming %s to %s: %s\n", target_name.c_str(), child_name.c_str(), err.c_str());
+                exit(1);
+            }
+            if (!res["succeeded"].bool_value())
+            {
+                fprintf(
+                    stderr, "Parent (%s), child (%s), or one of its children"
+                    " configuration was modified during rename\n", target_name.c_str(), child_name.c_str()
+                );
+                exit(1);
+            }
+            printf("Layer %s renamed to %s\n", target_name.c_str(), child_name.c_str());
+            parent->ringloop->wakeup();
+        });
+    }
+
+    void delete_inode_config(inode_t cur)
+    {
+        auto cur_cfg_it = parent->cli->st_cli.inode_config.find(cur);
+        if (cur_cfg_it == parent->cli->st_cli.inode_config.end())
+        {
+            fprintf(stderr, "Inode 0x%lx disappeared\n", cur);
+            exit(1);
+        }
+        inode_config_t *cur_cfg = &cur_cfg_it->second;
+        std::string cur_name = cur_cfg->name;
+        std::string cur_cfg_key = base64_encode(
+            parent->cli->st_cli.etcd_prefix+
+            "/config/inode/"+std::to_string(INODE_POOL(cur))+
+            "/"+std::to_string(INODE_NO_POOL(cur))
+        );
+        parent->waiting++;
+        parent->cli->st_cli.etcd_txn_slow(json11::Json::object {
+            { "compare", json11::Json::array {
+                json11::Json::object {
+                    { "target", "MOD" },
+                    { "key", cur_cfg_key },
+                    { "result", "LESS" },
+                    { "mod_revision", cur_cfg->mod_revision+1 },
+                },
+            } },
+            { "success", json11::Json::array {
+                json11::Json::object {
+                    { "request_delete_range", json11::Json::object {
+                        { "key", cur_cfg_key },
+                    } },
+                },
+                json11::Json::object {
+                    { "request_delete_range", json11::Json::object {
+                        { "key", base64_encode(parent->cli->st_cli.etcd_prefix+"/index/image/"+cur_name) },
+                    } },
+                },
+            } },
+        }, [this, cur_name](std::string err, json11::Json res)
+        {
+            parent->waiting--;
+            if (err != "")
+            {
+                fprintf(stderr, "Error deleting %s: %s\n", cur_name.c_str(), err.c_str());
+                exit(1);
+            }
+            if (!res["succeeded"].bool_value())
+            {
+                fprintf(stderr, "Layer %s configuration was modified during deletion\n", cur_name.c_str());
+                exit(1);
+            }
+            printf("Layer %s deleted\n", cur_name.c_str());
+            parent->ringloop->wakeup();
+        });
+    }
+
+    void start_merge_child(inode_t child_inode, inode_t target_inode)
+    {
+        auto child_it = parent->cli->st_cli.inode_config.find(child_inode);
+        if (child_it == parent->cli->st_cli.inode_config.end())
+        {
+            fprintf(stderr, "Inode %ld disappeared\n", child_inode);
+            exit(1);
+        }
+        auto target_it = parent->cli->st_cli.inode_config.find(target_inode);
+        if (target_it == parent->cli->st_cli.inode_config.end())
+        {
+            fprintf(stderr, "Inode %ld disappeared\n", target_inode);
+            exit(1);
+        }
+        cb = parent->start_merge(json11::Json::object {
+            { "command", json11::Json::array{ "merge-data", from_name, child_it->second.name } },
+            { "target", target_it->second.name },
+            { "delete-source", false },
+            { "cas", use_cas },
+            { "fsync-interval", fsync_interval },
+        });
+    }
+
+    void start_delete_source(inode_t inode)
+    {
+        auto source = parent->cli->st_cli.inode_config.find(inode);
+        if (source == parent->cli->st_cli.inode_config.end())
+        {
+            fprintf(stderr, "Inode %ld disappeared\n", inode);
+            exit(1);
+        }
+        cb = parent->start_rm(json11::Json::object {
+            { "inode", inode },
+            { "pool", (uint64_t)INODE_POOL(inode) },
+            { "fsync-interval", fsync_interval },
+        });
    }
 };

-std::function<bool(void)> cli_tool_t::start_rm(json11::Json cfg)
+std::function<bool(void)> cli_tool_t::start_snap_rm(json11::Json cfg)
 {
-    auto remover = new rm_inode_t();
-    remover->parent = this;
-    remover->inode = cfg["inode"].uint64_value();
-    remover->pool_id = cfg["pool"].uint64_value();
-    if (remover->pool_id)
+    json11::Json::array cmd = cfg["command"].array_items();
+    auto snap_remover = new snap_remover_t();
+    snap_remover->parent = this;
+    snap_remover->from_name = cmd.size() > 1 ? cmd[1].string_value() : "";
+    snap_remover->to_name = cmd.size() > 2 ? cmd[2].string_value() : "";
+    if (snap_remover->from_name == "")
    {
-        remover->inode = (remover->inode & ((1l << (64-POOL_ID_BITS)) - 1)) | (((uint64_t)remover->pool_id) << (64-POOL_ID_BITS));
-    }
-    remover->pool_id = INODE_POOL(remover->inode);
-    if (!remover->pool_id)
-    {
-        fprintf(stderr, "pool is missing\n");
+        fprintf(stderr, "Layer to remove argument is missing\n");
        exit(1);
    }
-    remover->min_offset = cfg["min-offset"].uint64_value();
-    return [remover]()
+    if (snap_remover->to_name == "")
    {
-        if (remover->loop())
+        snap_remover->to_name = snap_remover->from_name;
+    }
+    snap_remover->fsync_interval = cfg["fsync-interval"].uint64_value();
+    if (!snap_remover->fsync_interval)
+        snap_remover->fsync_interval = 128;
+    if (!cfg["cas"].is_null())
+        snap_remover->use_cas = cfg["cas"].uint64_value() ? 2 : 0;
+    if (!cfg["writers_stopped"].is_null())
+        snap_remover->writers_stopped = true;
+    return [snap_remover]()
+    {
+        snap_remover->loop();
+        if (snap_remover->is_done())
        {
-            delete remover;
+            delete snap_remover;
            return true;
        }
        return false;
--- a/src/cli_rm_data.cpp
+++ b/src/cli_rm_data.cpp
@@ -0,0 +1,214 @@
+// Copyright (c) Vitaliy Filippov, 2019+
+// License: VNPL-1.1 (see README.md for details)
+
+#include "cli.h"
+#include "cluster_client.h"
+
+#define RM_LISTING 1
+#define RM_REMOVING 2
+#define RM_END 3
+
+struct rm_pg_t
+{
+    pg_num_t pg_num;
+    osd_num_t rm_osd_num;
+    std::set<object_id> objects;
+    std::set<object_id>::iterator obj_pos;
+    uint64_t obj_count = 0, obj_done = 0;
+    int state = 0;
+    int in_flight = 0;
+};
+
+struct rm_inode_t
+{
+    uint64_t inode = 0;
+    pool_id_t pool_id = 0;
+    uint64_t min_offset = 0;
+
+    cli_tool_t *parent = NULL;
+    inode_list_t *lister = NULL;
+    std::vector<rm_pg_t*> lists;
+    uint64_t total_count = 0, total_done = 0, total_prev_pct = 0;
+    uint64_t pgs_to_list = 0;
+    bool lists_done = false;
+    int state = 0;
+
+    void start_delete()
+    {
+        lister = parent->cli->list_inode_start(inode, [this](inode_list_t *lst,
+            std::set<object_id>&& objects, pg_num_t pg_num, osd_num_t primary_osd, int status)
+        {
+            rm_pg_t *rm = new rm_pg_t((rm_pg_t){
+                .pg_num = pg_num,
+                .rm_osd_num = primary_osd,
+                .objects = objects,
+                .obj_count = objects.size(),
+                .obj_done = 0,
+            });
+            if (min_offset == 0)
+            {
+                total_count += objects.size();
+            }
+            else
+            {
+                for (object_id oid: objects)
+                {
+                    if (oid.stripe >= min_offset)
+                    {
+                        total_count++;
+                    }
+                }
+            }
+            rm->obj_pos = rm->objects.begin();
+            lists.push_back(rm);
+            if (parent->list_first)
+            {
+                parent->cli->list_inode_next(lister, 1);
+            }
+            if (status & INODE_LIST_DONE)
+            {
+                lists_done = true;
+            }
+            pgs_to_list--;
+            continue_delete();
+        });
+        if (!lister)
+        {
+            fprintf(stderr, "Failed to list inode %lu from pool %u objects\n", INODE_NO_POOL(inode), INODE_POOL(inode));
+            exit(1);
+        }
+        pgs_to_list = parent->cli->list_pg_count(lister);
+        parent->cli->list_inode_next(lister, parent->parallel_osds);
+    }
+
+    void send_ops(rm_pg_t *cur_list)
+    {
+        if (parent->cli->msgr.osd_peer_fds.find(cur_list->rm_osd_num) ==
+            parent->cli->msgr.osd_peer_fds.end())
+        {
+            // Initiate connection
+            parent->cli->msgr.connect_peer(cur_list->rm_osd_num, parent->cli->st_cli.peer_states[cur_list->rm_osd_num]);
+            return;
+        }
+        while (cur_list->in_flight < parent->iodepth && cur_list->obj_pos != cur_list->objects.end())
+        {
+            if (cur_list->obj_pos->stripe >= min_offset)
+            {
+                osd_op_t *op = new osd_op_t();
+                op->op_type = OSD_OP_OUT;
+                // Already checked that it exists above, but anyway
+                op->peer_fd = parent->cli->msgr.osd_peer_fds.at(cur_list->rm_osd_num);
+                op->req = (osd_any_op_t){
+                    .rw = {
+                        .header = {
+                            .magic = SECONDARY_OSD_OP_MAGIC,
+                            .id = parent->cli->next_op_id(),
+                            .opcode = OSD_OP_DELETE,
+                        },
+                        .inode = cur_list->obj_pos->inode,
+                        .offset = cur_list->obj_pos->stripe,
+                        .len = 0,
+                    },
+                };
+                op->callback = [this, cur_list](osd_op_t *op)
+                {
+                    cur_list->in_flight--;
+                    if (op->reply.hdr.retval < 0)
+                    {
+                        fprintf(stderr, "Failed to remove object %lx:%lx from PG %u (OSD %lu) (retval=%ld)\n",
+                            op->req.rw.inode, op->req.rw.offset,
+                            cur_list->pg_num, cur_list->rm_osd_num, op->reply.hdr.retval);
+                    }
+                    delete op;
+                    cur_list->obj_done++;
+                    total_done++;
+                    continue_delete();
+                };
+                cur_list->in_flight++;
+                parent->cli->msgr.outbox_push(op);
+            }
+            cur_list->obj_pos++;
+        }
+    }
+
+    void continue_delete()
+    {
+        if (parent->list_first && !lists_done)
+        {
+            return;
+        }
+        for (int i = 0; i < lists.size(); i++)
+        {
+            if (!lists[i]->in_flight && lists[i]->obj_pos == lists[i]->objects.end())
+            {
+                delete lists[i];
+                lists.erase(lists.begin()+i, lists.begin()+i+1);
+                i--;
+                if (!lists_done)
+                {
+                    parent->cli->list_inode_next(lister, 1);
+                }
+            }
+            else
+            {
+                send_ops(lists[i]);
+            }
+        }
+        if (parent->progress && total_count > 0 && total_done*1000/total_count != total_prev_pct)
+        {
+            printf("\rRemoved %lu/%lu objects, %lu more PGs to list...", total_done, total_count, pgs_to_list);
+            total_prev_pct = total_done*1000/total_count;
+        }
+        if (lists_done && !lists.size())
+        {
+            printf("Done, inode %lu in pool %u data removed\n", INODE_NO_POOL(inode), pool_id);
+            state = 2;
+        }
+    }
+
+    bool loop()
+    {
+        if (state == 0)
+        {
+            start_delete();
+            state = 1;
+        }
+        else if (state == 1)
+        {
+            continue_delete();
+        }
+        else if (state == 2)
+        {
+            return true;
+        }
+        return false;
+    }
+};
+
+std::function<bool(void)> cli_tool_t::start_rm(json11::Json cfg)
+{
+    auto remover = new rm_inode_t();
+    remover->parent = this;
+    remover->inode = cfg["inode"].uint64_value();
+    remover->pool_id = cfg["pool"].uint64_value();
+    if (remover->pool_id)
+    {
+        remover->inode = (remover->inode & ((1l << (64-POOL_ID_BITS)) - 1)) | (((uint64_t)remover->pool_id) << (64-POOL_ID_BITS));
+    }
+    remover->pool_id = INODE_POOL(remover->inode);
+    if (!remover->pool_id)
+    {
+        fprintf(stderr, "pool is missing\n");
+        exit(1);
+    }
+    remover->min_offset = cfg["min-offset"].uint64_value();
+    return [remover]()
+    {
+        if (remover->loop())
+        {
+            delete remover;
+            return true;
+        }
+        return false;
+    };
+}
--- a/src/cli_snap_rm.cpp
+++ b/src/cli_snap_rm.cpp
@@ -1,568 +0,0 @@
-// Copyright (c) Vitaliy Filippov, 2019+
-// License: VNPL-1.1 (see README.md for details)
-
-#include <fcntl.h>
-#include "cli.h"
-#include "cluster_client.h"
-#include "base64.h"
-
-// Remove layer(s): similar to merge, but alters metadata and processes multiple merge targets
-//
-// Exactly one child of the requested layers may be merged using the "inverted" workflow,
-// where we merge it "down" into one of the "to-be-removed" layers and then rename the
-// "to-be-removed" layer to the child. It may be done either if all writers are stopped
-// before trying to delete layers (which is signaled by --writers-stopped) or if that child
-// is a read-only layer (snapshot) itself.
-//
-// This "inverted" workflow trades copying data of one of the deleted layers for copying
-// data of one child of the chain which is also a child of the "traded" layer. So we
-// choose the (parent,child) pair which has the largest difference between "parent" and
-// "child" inode sizes.
-//
-// All other children of the chain are processed by iterating though them, merging removed
-// parents into them and rebasing them to the last layer which isn't a member of the removed
-// chain.
-//
-// Example:
-//
-// <parent> - <from> - <layer 2> - <to> - <child 1>
-//                 \           \       \- <child 2>
-//                  \           \- <child 3>
-//                   \-<child 4>
-//
-// 1) Find optimal pair for the "reverse" scenario
-//    Imagine that it's (<layer 2>, <child 1>) in this example
-// 2) Process all children except <child 1>:
-//    - Merge <from>..<to> to <child 2>
-//    - Set <child 2> parent to <parent>
-//    - Repeat for others
-// 3) Process <child 1>:
-//    - Merge <from>..<child 1> to <layer 2>
-//    - Set <layer 2> parent to <parent>
-//    - Rename <layer 2> to <child 1>
-// 4) Delete other layers of the chain (<from>, <to>)
-struct snap_remover_t
-{
-    cli_tool_t *parent;
-
-    // remove from..to
-    std::string from_name, to_name;
-    // writers are stopped, we can safely change writable layers
-    bool writers_stopped = false;
-    // use CAS writes (0 = never, 1 = auto, 2 = always)
-    int use_cas = 1;
-    // interval between fsyncs
-    int fsync_interval = 128;
-
-    std::map<inode_t,int> sources;
-    std::map<inode_t,uint64_t> inode_used;
-    std::vector<inode_t> merge_children;
-    std::vector<inode_t> chain_list;
-    std::map<inode_t,int> inverse_candidates;
-    inode_t inverse_parent = 0, inverse_child = 0;
-    inode_t new_parent = 0;
-    int state = 0;
-    int current_child = 0;
-    std::function<bool(void)> cb;
-
-    bool is_done()
-    {
-        return state == 9;
-    }
-
-    void loop()
-    {
-        if (state == 1)
-            goto resume_1;
-        else if (state == 2)
-            goto resume_2;
-        else if (state == 3)
-            goto resume_3;
-        else if (state == 4)
-            goto resume_4;
-        else if (state == 5)
-            goto resume_5;
-        else if (state == 6)
-            goto resume_6;
-        else if (state == 7)
-            goto resume_7;
-        else if (state == 8)
-            goto resume_8;
-        else if (state == 9)
-            goto resume_9;
-        // Get children to merge
-        get_merge_children();
-        // Try to select an inode for the "inverse" optimized scenario
-        // Read statistics from etcd to do it
-        read_stats();
-        state = 1;
-resume_1:
-        if (parent->waiting > 0)
-            return;
-        choose_inverse_candidate();
-        // Merge children one by one, except our "inverse" child
-        for (current_child = 0; current_child < merge_children.size(); current_child++)
-        {
-            if (merge_children[current_child] == inverse_child)
-                continue;
-            start_merge_child(merge_children[current_child], merge_children[current_child]);
-resume_2:
-            while (!cb())
-            {
-                state = 2;
-                return;
-            }
-            cb = NULL;
-            parent->change_parent(merge_children[current_child], new_parent);
-            state = 3;
-resume_3:
-            if (parent->waiting > 0)
-                return;
-        }
-        // Merge our "inverse" child into our "inverse" parent
-        if (inverse_child != 0)
-        {
-            start_merge_child(inverse_child, inverse_parent);
-resume_4:
-            while (!cb())
-            {
-                state = 4;
-                return;
-            }
-            cb = NULL;
-            // Delete "inverse" child data
-            start_delete_source(inverse_child);
-resume_5:
-            while (!cb())
-            {
-                state = 5;
-                return;
-            }
-            cb = NULL;
-            // Delete "inverse" child metadata, rename parent over it,
-            // and also change parent links of the previous "inverse" child
-            rename_inverse_parent();
-            state = 6;
-resume_6:
-            if (parent->waiting > 0)
-                return;
-        }
-        // Delete parents, except the "inverse" one
-        for (current_child = 0; current_child < chain_list.size(); current_child++)
-        {
-            if (chain_list[current_child] == inverse_parent)
-                continue;
-            start_delete_source(chain_list[current_child]);
-resume_7:
-            while (!cb())
-            {
-                state = 7;
-                return;
-            }
-            cb = NULL;
-            delete_inode_config(chain_list[current_child]);
-            state = 8;
-resume_8:
-            if (parent->waiting > 0)
-                return;
-        }
-        state = 9;
-resume_9:
-        // Done
-        return;
-    }
-
-    void get_merge_children()
-    {
-        // Get all children of from..to
-        inode_config_t *from_cfg = parent->get_inode_cfg(from_name);
-        inode_config_t *to_cfg = parent->get_inode_cfg(to_name);
-        // Check that to_cfg is actually a child of from_cfg
-        // FIXME de-copypaste the following piece of code with snap_merger_t
-        inode_config_t *cur = to_cfg;
-        chain_list.push_back(cur->num);
-        while (cur->num != from_cfg->num && cur->parent_id != 0)
-        {
-            auto it = parent->cli->st_cli.inode_config.find(cur->parent_id);
-            if (it == parent->cli->st_cli.inode_config.end())
-            {
-                fprintf(stderr, "Parent inode of layer %s (id %ld) not found\n", cur->name.c_str(), cur->parent_id);
-                exit(1);
-            }
-            cur = &it->second;
-            chain_list.push_back(cur->num);
-        }
-        if (cur->num != from_cfg->num)
-        {
-            fprintf(stderr, "Layer %s is not a child of %s\n", to_name.c_str(), from_name.c_str());
-            exit(1);
-        }
-        new_parent = from_cfg->parent_id;
-        // Calculate ranks
-        int i = chain_list.size()-1;
-        for (inode_t item: chain_list)
-        {
-            sources[item] = i--;
-        }
-        for (auto & ic: parent->cli->st_cli.inode_config)
-        {
-            if (!ic.second.parent_id)
-            {
-                continue;
-            }
-            auto it = sources.find(ic.second.parent_id);
-            if (it != sources.end() && sources.find(ic.second.num) == sources.end())
-            {
-                merge_children.push_back(ic.second.num);
-                if (ic.second.readonly || writers_stopped)
-                {
-                    inverse_candidates[ic.second.num] = it->second;
-                }
-            }
-        }
-    }
-
-    void read_stats()
-    {
-        if (inverse_candidates.size() == 0)
-        {
-            return;
-        }
-        json11::Json::array reads;
-        for (auto cp: inverse_candidates)
-        {
-            inode_t inode = cp.first;
-            reads.push_back(json11::Json::object {
-                { "request_range", json11::Json::object {
-                    { "key", base64_encode(
-                        parent->cli->st_cli.etcd_prefix+
-                        "/inode/stats/"+std::to_string(INODE_POOL(inode))+
-                        "/"+std::to_string(INODE_NO_POOL(inode))
-                    ) },
-                } }
-            });
-        }
-        for (auto cp: sources)
-        {
-            inode_t inode = cp.first;
-            reads.push_back(json11::Json::object {
-                { "request_range", json11::Json::object {
-                    { "key", base64_encode(
-                        parent->cli->st_cli.etcd_prefix+
-                        "/inode/stats/"+std::to_string(INODE_POOL(inode))+
-                        "/"+std::to_string(INODE_NO_POOL(inode))
-                    ) },
-                } }
-            });
-        }
-        parent->waiting++;
-        parent->cli->st_cli.etcd_txn_slow(json11::Json::object {
-            { "success", reads },
-        }, [this](std::string err, json11::Json data)
-        {
-            parent->waiting--;
-            if (err != "")
-            {
-                fprintf(stderr, "Error reading layer statistics from etcd: %s\n", err.c_str());
-                exit(1);
-            }
-            for (auto inode_result: data["responses"].array_items())
-            {
-                auto kv = parent->cli->st_cli.parse_etcd_kv(inode_result["kvs"][0]);
-                pool_id_t pool_id = 0;
-                inode_t inode = 0;
-                char null_byte = 0;
-                sscanf(kv.key.c_str() + parent->cli->st_cli.etcd_prefix.length()+13, "%u/%lu%c", &pool_id, &inode, &null_byte);
-                if (!inode || null_byte != 0)
-                {
-                    fprintf(stderr, "Bad key returned from etcd: %s\n", kv.key.c_str());
-                    exit(1);
-                }
-                auto pool_cfg_it = parent->cli->st_cli.pool_config.find(pool_id);
-                if (pool_cfg_it == parent->cli->st_cli.pool_config.end())
-                {
-                    fprintf(stderr, "Pool %u does not exist\n", pool_id);
-                    exit(1);
-                }
-                inode = INODE_WITH_POOL(pool_id, inode);
-                auto & pool_cfg = pool_cfg_it->second;
-                uint64_t used_bytes = kv.value["raw_used"].uint64_value() / pool_cfg.pg_size;
-                if (pool_cfg.scheme != POOL_SCHEME_REPLICATED)
-                {
-                    used_bytes *= (pool_cfg.pg_size - pool_cfg.parity_chunks);
-                }
-                inode_used[inode] = used_bytes;
-            }
-            parent->ringloop->wakeup();
-        });
-    }
-
-    void choose_inverse_candidate()
-    {
-        uint64_t max_diff = 0;
-        for (auto cp: inverse_candidates)
-        {
-            inode_t child = cp.first;
-            uint64_t child_used = inode_used[child];
-            int rank = cp.second;
-            for (int i = chain_list.size()-rank; i < chain_list.size(); i++)
-            {
-                inode_t parent = chain_list[i];
-                uint64_t parent_used = inode_used[parent];
-                if (parent_used > child_used && (!max_diff || max_diff < (parent_used-child_used)))
-                {
-                    max_diff = (parent_used-child_used);
-                    inverse_parent = parent;
-                    inverse_child = child;
-                }
-            }
-        }
-    }
-
-    void rename_inverse_parent()
-    {
-        auto child_it = parent->cli->st_cli.inode_config.find(inverse_child);
-        if (child_it == parent->cli->st_cli.inode_config.end())
-        {
-            fprintf(stderr, "Inode %ld disappeared\n", inverse_child);
-            exit(1);
-        }
-        auto target_it = parent->cli->st_cli.inode_config.find(inverse_parent);
-        if (target_it == parent->cli->st_cli.inode_config.end())
-        {
-            fprintf(stderr, "Inode %ld disappeared\n", inverse_parent);
-            exit(1);
-        }
-        inode_config_t *child_cfg = &child_it->second;
-        inode_config_t *target_cfg = &target_it->second;
-        std::string child_name = child_cfg->name;
-        std::string target_name = target_cfg->name;
-        std::string child_cfg_key = base64_encode(
-            parent->cli->st_cli.etcd_prefix+
-            "/config/inode/"+std::to_string(INODE_POOL(inverse_child))+
-            "/"+std::to_string(INODE_NO_POOL(inverse_child))
-        );
-        std::string target_cfg_key = base64_encode(
-            parent->cli->st_cli.etcd_prefix+
-            "/config/inode/"+std::to_string(INODE_POOL(inverse_parent))+
-            "/"+std::to_string(INODE_NO_POOL(inverse_parent))
-        );
-        // Fill new configuration
-        inode_config_t new_cfg = *child_cfg;
-        new_cfg.num = target_cfg->num;
-        new_cfg.parent_id = new_parent;
-        json11::Json::array cmp = json11::Json::array {
-            json11::Json::object {
-                { "target", "MOD" },
-                { "key", child_cfg_key },
-                { "result", "LESS" },
-                { "mod_revision", child_cfg->mod_revision+1 },
-            },
-            json11::Json::object {
-                { "target", "MOD" },
-                { "key", target_cfg_key },
-                { "result", "LESS" },
-                { "mod_revision", target_cfg->mod_revision+1 },
-            },
-        };
-        json11::Json::array txn = json11::Json::array {
-            json11::Json::object {
-                { "request_delete_range", json11::Json::object {
-                    { "key", child_cfg_key },
-                } },
-            },
-            json11::Json::object {
-                { "request_put", json11::Json::object {
-                    { "key", target_cfg_key },
-                    { "value", base64_encode(json11::Json(parent->cli->st_cli.serialize_inode_cfg(&new_cfg)).dump()) },
-                } },
-            },
-            json11::Json::object {
-                { "request_put", json11::Json::object {
-                    { "key", base64_encode(parent->cli->st_cli.etcd_prefix+"/index/image/"+child_cfg->name) },
-                    { "value", base64_encode(json11::Json({
-                        { "id", INODE_NO_POOL(inverse_parent) },
-                        { "pool_id", (uint64_t)INODE_POOL(inverse_parent) },
-                    }).dump()) },
-                } },
-            },
-        };
-        // Reparent children of inverse_child
-        for (auto & cp: parent->cli->st_cli.inode_config)
-        {
-            if (cp.second.parent_id == child_cfg->num)
-            {
-                auto cp_cfg = cp.second;
-                cp_cfg.parent_id = inverse_parent;
-                auto cp_key = base64_encode(
-                    parent->cli->st_cli.etcd_prefix+
-                    "/config/inode/"+std::to_string(INODE_POOL(cp.second.num))+
-                    "/"+std::to_string(INODE_NO_POOL(cp.second.num))
-                );
-                cmp.push_back(json11::Json::object {
-                    { "target", "MOD" },
-                    { "key", cp_key },
-                    { "result", "LESS" },
-                    { "mod_revision", cp.second.mod_revision+1 },
-                });
-                txn.push_back(json11::Json::object {
-                    { "request_put", json11::Json::object {
-                        { "key", cp_key },
-                        { "value", base64_encode(json11::Json(parent->cli->st_cli.serialize_inode_cfg(&cp_cfg)).dump()) },
-                    } },
-                });
-            }
-        }
-        parent->waiting++;
-        parent->cli->st_cli.etcd_txn_slow(json11::Json::object {
-            { "compare", cmp },
-            { "success", txn },
-        }, [this, target_name, child_name](std::string err, json11::Json res)
-        {
-            parent->waiting--;
-            if (err != "")
-            {
-                fprintf(stderr, "Error renaming %s to %s: %s\n", target_name.c_str(), child_name.c_str(), err.c_str());
-                exit(1);
-            }
-            if (!res["succeeded"].bool_value())
-            {
-                fprintf(
-                    stderr, "Parent (%s), child (%s), or one of its children"
-                    " configuration was modified during rename\n", target_name.c_str(), child_name.c_str()
-                );
-                exit(1);
-            }
-            printf("Layer %s renamed to %s\n", target_name.c_str(), child_name.c_str());
-            parent->ringloop->wakeup();
-        });
-    }
-
-    void delete_inode_config(inode_t cur)
-    {
-        auto cur_cfg_it = parent->cli->st_cli.inode_config.find(cur);
-        if (cur_cfg_it == parent->cli->st_cli.inode_config.end())
-        {
-            fprintf(stderr, "Inode 0x%lx disappeared\n", cur);
-            exit(1);
-        }
-        inode_config_t *cur_cfg = &cur_cfg_it->second;
-        std::string cur_name = cur_cfg->name;
-        std::string cur_cfg_key = base64_encode(
-            parent->cli->st_cli.etcd_prefix+
-            "/config/inode/"+std::to_string(INODE_POOL(cur))+
-            "/"+std::to_string(INODE_NO_POOL(cur))
-        );
-        parent->waiting++;
-        parent->cli->st_cli.etcd_txn_slow(json11::Json::object {
-            { "compare", json11::Json::array {
-                json11::Json::object {
-                    { "target", "MOD" },
-                    { "key", cur_cfg_key },
-                    { "result", "LESS" },
-                    { "mod_revision", cur_cfg->mod_revision+1 },
-                },
-            } },
-            { "success", json11::Json::array {
-                json11::Json::object {
-                    { "request_delete_range", json11::Json::object {
-                        { "key", cur_cfg_key },
-                    } },
-                },
-                json11::Json::object {
-                    { "request_delete_range", json11::Json::object {
-                        { "key", base64_encode(parent->cli->st_cli.etcd_prefix+"/index/image/"+cur_name) },
-                    } },
-                },
-            } },
-        }, [this, cur_name](std::string err, json11::Json res)
-        {
-            parent->waiting--;
-            if (err != "")
-            {
-                fprintf(stderr, "Error deleting %s: %s\n", cur_name.c_str(), err.c_str());
-                exit(1);
-            }
-            if (!res["succeeded"].bool_value())
-            {
-                fprintf(stderr, "Layer %s configuration was modified during deletion\n", cur_name.c_str());
-                exit(1);
-            }
-            printf("Layer %s deleted\n", cur_name.c_str());
-            parent->ringloop->wakeup();
-        });
-    }
-
-    void start_merge_child(inode_t child_inode, inode_t target_inode)
-    {
-        auto child_it = parent->cli->st_cli.inode_config.find(child_inode);
-        if (child_it == parent->cli->st_cli.inode_config.end())
-        {
-            fprintf(stderr, "Inode %ld disappeared\n", child_inode);
-            exit(1);
-        }
-        auto target_it = parent->cli->st_cli.inode_config.find(target_inode);
-        if (target_it == parent->cli->st_cli.inode_config.end())
-        {
-            fprintf(stderr, "Inode %ld disappeared\n", target_inode);
-            exit(1);
-        }
-        cb = parent->start_merge(json11::Json::object {
-            { "command", json11::Json::array{ "merge-data", from_name, child_it->second.name } },
-            { "target", target_it->second.name },
-            { "delete-source", false },
-            { "cas", use_cas },
-            { "fsync-interval", fsync_interval },
-        });
-    }
-
-    void start_delete_source(inode_t inode)
-    {
-        auto source = parent->cli->st_cli.inode_config.find(inode);
-        if (source == parent->cli->st_cli.inode_config.end())
-        {
-            fprintf(stderr, "Inode %ld disappeared\n", inode);
-            exit(1);
-        }
-        cb = parent->start_rm(json11::Json::object {
-            { "inode", inode },
-            { "pool", (uint64_t)INODE_POOL(inode) },
-            { "fsync-interval", fsync_interval },
-        });
-    }
-};
-
-std::function<bool(void)> cli_tool_t::start_snap_rm(json11::Json cfg)
-{
-    json11::Json::array cmd = cfg["command"].array_items();
-    auto snap_remover = new snap_remover_t();
-    snap_remover->parent = this;
-    snap_remover->from_name = cmd.size() > 1 ? cmd[1].string_value() : "";
-    snap_remover->to_name = cmd.size() > 2 ? cmd[2].string_value() : "";
-    if (snap_remover->from_name == "")
-    {
-        fprintf(stderr, "Layer to remove argument is missing\n");
-        exit(1);
-    }
-    if (snap_remover->to_name == "")
-    {
-        snap_remover->to_name = snap_remover->from_name;
-    }
-    snap_remover->fsync_interval = cfg["fsync-interval"].uint64_value();
-    if (!snap_remover->fsync_interval)
-        snap_remover->fsync_interval = 128;
-    if (!cfg["cas"].is_null())
-        snap_remover->use_cas = cfg["cas"].uint64_value() ? 2 : 0;
-    if (!cfg["writers_stopped"].is_null())
-        snap_remover->writers_stopped = true;
-    return [snap_remover]()
-    {
-        snap_remover->loop();
-        if (snap_remover->is_done())
-        {
-            delete snap_remover;
-            return true;
-        }
-        return false;
-    };
-}
--- a/src/cluster_client.cpp
+++ b/src/cluster_client.cpp
@@ -143,7 +143,7 @@ void cluster_client_t::calc_wait(cluster_op_t *op)
    }
    else /* if (op->opcode == OSD_OP_READ || op->opcode == OSD_OP_READ_BITMAP) */
    {
-        for (auto prev = op->prev; prev; prev = prev->prev)
+        for (auto prev = op_queue_head; prev && prev != op; prev = prev->next)
        {
            if (prev->opcode == OSD_OP_WRITE && prev->flags & OP_FLUSH_BUFFER)
            {
@@ -151,7 +151,7 @@ void cluster_client_t::calc_wait(cluster_op_t *op)
            }
            else if (prev->opcode == OSD_OP_WRITE || prev->opcode == OSD_OP_READ || prev->opcode == OSD_OP_READ_BITMAP)
            {
-                // Flushes are always in the beginning
+                // Flushes are always in the beginning (we're scanning from the beginning of the queue)
                break;
            }
        }
@@ -172,6 +172,7 @@ void cluster_client_t::inc_wait(uint64_t opcode, uint64_t flags, cluster_op_t *n
                (next->opcode == OSD_OP_READ || next->opcode == OSD_OP_READ_BITMAP) && (flags & OP_FLUSH_BUFFER))
            {
                next->prev_wait += inc;
+                assert(next->prev_wait >= 0);
                if (!next->prev_wait)
                {
                    if (next->opcode == OSD_OP_SYNC)
@@ -191,6 +192,7 @@ void cluster_client_t::inc_wait(uint64_t opcode, uint64_t flags, cluster_op_t *n
            if (next->opcode == OSD_OP_SYNC || next->opcode == OSD_OP_WRITE)
            {
                next->prev_wait += inc;
+                assert(next->prev_wait >= 0);
                if (!next->prev_wait)
                {
                    if (next->opcode == OSD_OP_SYNC)
--- a/src/cluster_client_list.cpp
+++ b/src/cluster_client_list.cpp
@@ -200,7 +200,8 @@ void cluster_client_t::send_list(inode_list_osd_t *cur_list)
    auto & pool_cfg = st_cli.pool_config[cur_list->pg->lst->pool_id];
    osd_op_t *op = new osd_op_t();
    op->op_type = OSD_OP_OUT;
-    op->peer_fd = msgr.osd_peer_fds[cur_list->osd_num];
+    // Already checked that it exists above, but anyway
+    op->peer_fd = msgr.osd_peer_fds.at(cur_list->osd_num);
    op->req = (osd_any_op_t){
        .sec_list = {
            .header = {
--- a/src/epoll_manager.cpp
+++ b/src/epoll_manager.cpp
@@ -13,6 +13,7 @@
 epoll_manager_t::epoll_manager_t(ring_loop_t *ringloop)
 {
    this->ringloop = ringloop;
+    this->pending = false;

    epoll_fd = epoll_create(1);
    if (epoll_fd < 0)
@@ -22,11 +23,19 @@ epoll_manager_t::epoll_manager_t(ring_loop_t *ringloop)

    tfd = new timerfd_manager_t([this](int fd, bool wr, std::function<void(int, int)> handler) { set_fd_handler(fd, wr, handler); });

+    consumer.loop = [this]()
+    {
+        if (pending)
+            handle_epoll_events();
+    };
+    ringloop->register_consumer(&consumer);
+
    handle_epoll_events();
 }

 epoll_manager_t::~epoll_manager_t()
 {
+    ringloop->unregister_consumer(&consumer);
    if (tfd)
    {
        delete tfd;
@@ -64,8 +73,13 @@ void epoll_manager_t::handle_epoll_events()
    io_uring_sqe *sqe = ringloop->get_sqe();
    if (!sqe)
    {
-        throw std::runtime_error("can't get SQE, will fall out of sync with EPOLLET");
+        // Don't handle epoll events until we manage to post the next event handler
+        // otherwise we'll fall out of sync with EPOLLET
+        pending = true;
+        ringloop->wakeup();
+        return;
    }
+    pending = false;
    ring_data_t *data = ((ring_data_t*)sqe->user_data);
    my_uring_prep_poll_add(sqe, epoll_fd, POLLIN);
    data->callback = [this](ring_data_t *data)
--- a/src/epoll_manager.h
+++ b/src/epoll_manager.h
@@ -11,6 +11,8 @@
 class epoll_manager_t
 {
    int epoll_fd;
+    bool pending;
+    ring_consumer_t consumer;
    ring_loop_t *ringloop;
    std::map<int, std::function<void(int, int)>> epoll_handlers;
 public:
--- a/src/fio_cluster.cpp
+++ b/src/fio_cluster.cpp
@@ -351,9 +351,9 @@ static enum fio_q_status sec_queue(struct thread_data *td, struct io_u *io)
        }
        else
        {
-            printf("+++ %s 0x%lx 0x%llx+%llx\n",
+            printf("+++ %s 0x%lx 0x%llx+%lx\n",
                io->ddir == DDIR_READ ? "READ" : "WRITE",
-                (uint64_t)io, io->offset, io->xfer_buflen);
+                (uint64_t)io, io->offset, (uint64_t)io->xfer_buflen);
        }
    }

--- a/src/fio_headers.h
+++ b/src/fio_headers.h
@@ -1,4 +1,3 @@
-extern "C" {
 // Kill atomics in fio headers
 #define _STDATOMIC_H
 #include "fio/arch/arch.h"
@@ -11,6 +10,7 @@ extern "C" {
 #define CONFIG_HAVE_GETTID
 #define CONFIG_SYNC_FILE_RANGE
 #define CONFIG_PWRITEV2
+extern "C" {
 #include "fio/fio.h"
 #include "fio/optgroup.h"
 }
--- a/src/fio_sec_osd.cpp
+++ b/src/fio_sec_osd.cpp
@@ -170,14 +170,14 @@ static int sec_init(struct thread_data *td)
    bsd->block_order = o->block_order == 0 ? 17 : o->block_order;
    bsd->block_size = 1 << o->block_order;

-    sockaddr addr;
+    sockaddr_storage addr;
    if (!string_to_addr(std::string(o->host ? o->host : "127.0.0.1"), false, o->port > 0 ? o->port : 11203, &addr))
    {
        fprintf(stderr, "server address: %s is not valid\n", o->host ? o->host : "127.0.0.1");
        return 1;
    }

-    bsd->connect_fd = socket(addr.sa_family, SOCK_STREAM, 0);
+    bsd->connect_fd = socket(addr.ss_family, SOCK_STREAM, 0);
    if (bsd->connect_fd < 0)
    {
        perror("socket");
@@ -192,11 +192,16 @@ static int sec_init(struct thread_data *td)
    setsockopt(bsd->connect_fd, SOL_TCP, TCP_NODELAY, &one, sizeof(one));
    if (o->zerocopy_send)
    {
+#ifndef SO_ZEROCOPY
+        perror("zerocopy send not supported on your system (socket.h misses SO_ZEROCOPY)");
+        return 1;
+#else
        if (setsockopt(bsd->connect_fd, SOL_SOCKET, SO_ZEROCOPY, &one, sizeof(one)) < 0)
        {
            perror("setsockopt zerocopy");
            return 1;
        }
+#endif
    }

    // FIXME: read config (block size) from OSD
@@ -306,7 +311,13 @@ static enum fio_q_status sec_queue(struct thread_data *td, struct io_u *io)
        iov[iovcnt++] = { .iov_base = io->xfer_buf, .iov_len = io->xfer_buflen };
        wtotal += io->xfer_buflen;
    }
-    if (sendv_blocking(bsd->connect_fd, iov, iovcnt, opt->zerocopy_send ? MSG_ZEROCOPY : 0) != wtotal)
+    if (sendv_blocking(bsd->connect_fd, iov, iovcnt,
+#ifdef SO_ZEROCOPY
+        opt->zerocopy_send ? MSG_ZEROCOPY : 0
+#else
+        0
+#endif
+    ) != wtotal)
    {
        perror("sendmsg");
        exit(1);
@@ -344,7 +355,7 @@ static int sec_getevents(struct thread_data *td, unsigned int min, unsigned int
        {
            if (reply.hdr.retval != io->xfer_buflen)
            {
-                fprintf(stderr, "Short read: retval = %ld instead of %llu\n", reply.hdr.retval, io->xfer_buflen);
+                fprintf(stderr, "Short read: retval = %ld instead of %lu\n", reply.hdr.retval, (uint64_t)io->xfer_buflen);
                exit(1);
            }
            // Support bitmap
@@ -369,7 +380,7 @@ static int sec_getevents(struct thread_data *td, unsigned int min, unsigned int
        {
            if (reply.hdr.retval != io->xfer_buflen)
            {
-                fprintf(stderr, "Short write: retval = %ld instead of %llu\n", reply.hdr.retval, io->xfer_buflen);
+                fprintf(stderr, "Short write: retval = %ld instead of %lu\n", reply.hdr.retval, (uint64_t)io->xfer_buflen);
                exit(1);
            }
        }
--- a/src/http_client.cpp
+++ b/src/http_client.cpp
@@ -62,9 +62,10 @@ struct http_co_t
    void run_cb_and_clear();
    void start_connection();
    void close_connection();
+    void next_request();
    void handle_events();
    void handle_connect_result();
-    void submit_read();
+    void submit_read(bool check_timeout);
    void submit_send();
    bool handle_read();
    void post_message(int type, const std::string & msg);
@@ -128,6 +129,7 @@ void http_co_t::run_cb_and_clear()
    // Call callback after clearing it because otherwise we may hit reenterability problems
    if (cb != NULL)
        cb(&parsed);
+    next_request();
 }

 void http_co_t::send_request(const std::string & host, const std::string & request,
@@ -161,17 +163,6 @@ void http_co_t::send_request(const std::string & host, const std::string & reque
    this->sent = 0;
    this->response_callback = response_callback;
    this->parsed = {};
-    if (request_timeout > 0)
-    {
-        timeout_id = tfd->set_timer(request_timeout, false, [this](int timer_id)
-        {
-            stackin();
-            close_connection();
-            parsed = { .error = "HTTP request timed out" };
-            run_cb_and_clear();
-            stackout();
-        });
-    }
    if (state == HTTP_CO_KEEPALIVE)
    {
        state = HTTP_CO_SENDING_REQUEST;
@@ -181,6 +172,28 @@ void http_co_t::send_request(const std::string & host, const std::string & reque
    {
        start_connection();
    }
+    // Do it _after_ state assignment because set_timer() can actually trigger
+    // other timers and requests (reenterability is our friend)
+    if (request_timeout > 0)
+    {
+        timeout_id = tfd->set_timer(request_timeout, false, [this](int timer_id)
+        {
+            stackin();
+            if (state == HTTP_CO_REQUEST_SENT)
+            {
+                // In case of high CPU load, we may not handle etcd responses in time
+                // For this case, first check the socket and only then terminate request with the timeout
+                submit_read(true);
+            }
+            else
+            {
+                close_connection();
+                parsed = { .error = "HTTP request timed out" };
+                run_cb_and_clear();
+            }
+            stackout();
+        });
+    }
    stackout();
 }

@@ -271,17 +284,19 @@ void http_co_t::close_connection()
 void http_co_t::start_connection()
 {
    stackin();
-    struct sockaddr addr;
+    struct sockaddr_storage addr;
    if (!string_to_addr(host.c_str(), 1, 80, &addr))
    {
+        close_connection();
        parsed = { .error = "Invalid address: "+host };
        run_cb_and_clear();
        stackout();
        return;
    }
-    peer_fd = socket(addr.sa_family, SOCK_STREAM, 0);
+    peer_fd = socket(addr.ss_family, SOCK_STREAM, 0);
    if (peer_fd < 0)
    {
+        close_connection();
        parsed = { .error = std::string("socket: ")+strerror(errno) };
        run_cb_and_clear();
        stackout();
@@ -323,7 +338,7 @@ void http_co_t::handle_events()
            epoll_events &= ~EPOLLOUT;
            if (epoll_events & EPOLLIN)
            {
-                submit_read();
+                submit_read(false);
            }
            else if (epoll_events & (EPOLLRDHUP|EPOLLERR))
            {
@@ -410,10 +425,11 @@ again:
    stackout();
 }

-void http_co_t::submit_read()
+void http_co_t::submit_read(bool check_timeout)
 {
    stackin();
    int res;
+again:
    if (rbuf.size() != READ_BUFFER_SIZE)
    {
        rbuf.resize(READ_BUFFER_SIZE);
@@ -428,7 +444,22 @@ void http_co_t::submit_read()
    }
    if (res == -EAGAIN || res == -EINTR)
    {
-        epoll_events = epoll_events & ~EPOLLIN;
+        if (check_timeout)
+        {
+            if (res == -EINTR)
+                goto again;
+            else
+            {
+                // Timeout happened and there is no data to read
+                close_connection();
+                parsed = { .error = "HTTP request timed out" };
+                run_cb_and_clear();
+            }
+        }
+        else
+        {
+            epoll_events = epoll_events & ~EPOLLIN;
+        }
    }
    else if (res <= 0)
    {
@@ -501,8 +532,11 @@ bool http_co_t::handle_read()
    if (state == HTTP_CO_HEADERS_RECEIVED && target_response_size > 0 && response.size() >= target_response_size)
    {
        std::swap(parsed.body, response);
-        response_callback(&parsed);
-        parsed.eof = true;
+        if (!keepalive)
+            close_connection();
+        else
+            state = HTTP_CO_KEEPALIVE;
+        run_cb_and_clear();
    }
    else if (state == HTTP_CO_CHUNKED && response.size() > 0)
    {
@@ -533,10 +567,14 @@ bool http_co_t::handle_read()
            response_callback(&parsed);
            parsed.body = "";
        }
-        if (parsed.eof && !want_streaming)
+        else if (parsed.eof)
        {
            // Normal response
-            response_callback(&parsed);
+            if (!keepalive)
+                close_connection();
+            else
+                state = HTTP_CO_KEEPALIVE;
+            run_cb_and_clear();
        }
    }
    else if (state == HTTP_CO_WEBSOCKET && response.size() > 0)
@@ -547,29 +585,20 @@ bool http_co_t::handle_read()
            parsed.body = "";
        }
    }
-    if (parsed.eof)
-    {
-        response_callback = NULL;
-        parsed = {};
-        if (!keepalive)
-        {
-            close_connection();
-        }
-        else
-        {
-            state = HTTP_CO_KEEPALIVE;
-            if (keepalive_queue.size() > 0)
-            {
-                auto next = keepalive_queue[0];
-                keepalive_queue.erase(keepalive_queue.begin(), keepalive_queue.begin()+1);
-                next();
-            }
-        }
-    }
    stackout();
    return true;
 }

+void http_co_t::next_request()
+{
+    if (keepalive_queue.size() > 0)
+    {
+        auto next = keepalive_queue[0];
+        keepalive_queue.erase(keepalive_queue.begin(), keepalive_queue.begin()+1);
+        next();
+    }
+}
+
 uint64_t stoull_full(const std::string & str, int base)
 {
    if (isspace(str[0]))
--- a/src/messenger.cpp
+++ b/src/messenger.cpp
@@ -222,13 +222,13 @@ void osd_messenger_t::try_connect_peer(uint64_t peer_osd)
 void osd_messenger_t::try_connect_peer_addr(osd_num_t peer_osd, const char *peer_host, int peer_port)
 {
    assert(peer_osd != this->osd_num);
-    struct sockaddr addr;
+    struct sockaddr_storage addr;
    if (!string_to_addr(peer_host, 0, peer_port, &addr))
    {
        on_connect_peer(peer_osd, -EINVAL);
        return;
    }
-    int peer_fd = socket(addr.sa_family, SOCK_STREAM, 0);
+    int peer_fd = socket(addr.ss_family, SOCK_STREAM, 0);
    if (peer_fd < 0)
    {
        on_connect_peer(peer_osd, -errno);
@@ -484,10 +484,10 @@ void osd_messenger_t::check_peer_config(osd_client_t *cl)
 void osd_messenger_t::accept_connections(int listen_fd)
 {
    // Accept new connections
-    sockaddr addr;
+    sockaddr_storage addr;
    socklen_t peer_addr_size = sizeof(addr);
    int peer_fd;
-    while ((peer_fd = accept(listen_fd, &addr, &peer_addr_size)) >= 0)
+    while ((peer_fd = accept(listen_fd, (sockaddr*)&addr, &peer_addr_size)) >= 0)
    {
        assert(peer_fd != 0);
        fprintf(stderr, "[OSD %lu] new client %d: connection from %s\n", this->osd_num, peer_fd,
--- a/src/messenger.h
+++ b/src/messenger.h
@@ -49,7 +49,7 @@ struct osd_client_t
 {
    int refs = 0;

-    sockaddr peer_addr;
+    sockaddr_storage peer_addr;
    int peer_port;
    int peer_fd;
    int peer_state;
--- a/src/msgr_stop.cpp
+++ b/src/msgr_stop.cpp
@@ -111,6 +111,10 @@ void osd_messenger_t::stop_client(int peer_fd, bool force, bool force_delete)
        {
            delete cl->read_op;
        }
+        else
+        {
+            cancel_op(cl->read_op);
+        }
        cl->read_op = NULL;
    }
    if (cl->osd_num)
--- a/src/nbd_proxy.cpp
+++ b/src/nbd_proxy.cpp
@@ -55,6 +55,15 @@ protected:
    iovec read_iov = { 0 };

 public:
+    ~nbd_proxy()
+    {
+        if (recv_buf)
+        {
+            free(recv_buf);
+            recv_buf = NULL;
+        }
+    }
+
    static json11::Json::object parse_args(int narg, const char *args[])
    {
        json11::Json::object cfg;
@@ -322,6 +331,9 @@ public:
        delete cli;
        delete epmgr;
        delete ringloop;
+        cli = NULL;
+        epmgr = NULL;
+        ringloop = NULL;
    }

    void load_module()
@@ -351,7 +363,8 @@ public:
        setsid();
        if (fork())
            exit(0);
-        chdir("/");
+        if (chdir("/") != 0)
+            fprintf(stderr, "Warning: Failed to chdir into /\n");
        close(0);
        close(1);
        close(2);
@@ -498,7 +511,7 @@ protected:
            goto end_unmap;
        }
        ioctl(nbd, NBD_SET_FLAGS, flags);
-        if (timeout >= 0)
+        if (timeout > 0)
        {
            r = ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout);
            if (r < 0)
@@ -513,7 +526,11 @@ protected:
        {
            goto end_unmap;
        }
-        write(qd_fd, "32768", 5);
+        r = write(qd_fd, "32768", 5);
+        if (r != 5)
+        {
+            fprintf(stderr, "Warning: Failed to configure max_sectors_kb\n");
+        }
        close(qd_fd);
        if (!fork())
        {
--- a/src/osd.cpp
+++ b/src/osd.cpp
@@ -3,6 +3,7 @@

 #include <sys/socket.h>
 #include <sys/poll.h>
+#include <sys/mman.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
@@ -53,6 +54,20 @@ osd_t::osd_t(const json11::Json & config, ring_loop_t *ringloop)
            autosync_writes = max_autosync;
    }

+    if (this->config["osd_memlock"] == "true" || this->config["osd_memlock"] == "1" || this->config["osd_memlock"] == "yes")
+    {
+        // Lock all OSD memory if requested
+        if (mlockall(MCL_CURRENT|MCL_FUTURE
+#ifdef MCL_ONFAULT
+            | MCL_ONFAULT
+#endif
+            ) != 0)
+        {
+            fprintf(stderr, "osd_memlock is set to true, but mlockall() failed: %s\n", strerror(errno));
+            exit(-1);
+        }
+    }
+
    this->tfd->set_timer(print_stats_interval*1000, true, [this](int timer_id)
    {
        print_stats();
@@ -185,46 +200,7 @@ void osd_t::bind_socket()

    // FIXME Support multiple listening sockets

-    sockaddr addr;
-    if (!string_to_addr(bind_address, 0, bind_port, &addr))
-    {
-        throw std::runtime_error("bind address "+bind_address+" is not valid");
-    }
-
-    listen_fd = socket(addr.sa_family, SOCK_STREAM, 0);
-    if (listen_fd < 0)
-    {
-        throw std::runtime_error(std::string("socket: ") + strerror(errno));
-    }
-    int enable = 1;
-    setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
-
-    if (bind(listen_fd, &addr, sizeof(addr)) < 0)
-    {
-        close(listen_fd);
-        throw std::runtime_error(std::string("bind: ") + strerror(errno));
-    }
-    if (bind_port == 0)
-    {
-        socklen_t len = sizeof(addr);
-        if (getsockname(listen_fd, (sockaddr *)&addr, &len) == -1)
-        {
-            close(listen_fd);
-            throw std::runtime_error(std::string("getsockname: ") + strerror(errno));
-        }
-        listening_port = ntohs(((sockaddr_in*)&addr)->sin_port);
-    }
-    else
-    {
-        listening_port = bind_port;
-    }
-
-    if (listen(listen_fd, listen_backlog) < 0)
-    {
-        close(listen_fd);
-        throw std::runtime_error(std::string("listen: ") + strerror(errno));
-    }
-
+    listen_fd = create_and_bind_socket(bind_address, bind_port, listen_backlog, &listening_port);
    fcntl(listen_fd, F_SETFL, fcntl(listen_fd, F_GETFL, 0) | O_NONBLOCK);

    epmgr->set_fd_handler(listen_fd, false, [this](int fd, int events)
--- a/src/osd.h
+++ b/src/osd.h
@@ -211,7 +211,7 @@ class osd_t
    // flushing, recovery and backfill
    void submit_pg_flush_ops(pg_t & pg);
    void handle_flush_op(bool rollback, pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, osd_num_t peer_osd, int retval);
-    void submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, bool rollback, osd_num_t peer_osd, int count, obj_ver_id *data);
+    bool submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, bool rollback, osd_num_t peer_osd, int count, obj_ver_id *data);
    bool pick_next_recovery(osd_recovery_op_t &op);
    void submit_recovery_op(osd_recovery_op_t *op);
    bool continue_recovery();
--- a/src/osd_cluster.cpp
+++ b/src/osd_cluster.cpp
@@ -457,7 +457,8 @@ void osd_t::renew_lease()
        if (err == "" && data["result"]["TTL"].string_value() == "")
        {
            // Die
-            throw std::runtime_error("etcd lease has expired");
+            fprintf(stderr, "Error refreshing etcd lease\n");
+            force_stop(1);
        }
        if (err != "")
        {
@@ -466,7 +467,8 @@ void osd_t::renew_lease()
            if (etcd_failed_attempts > st_cli.max_etcd_attempts)
            {
                // Die
-                throw std::runtime_error("Cluster connection failed");
+                fprintf(stderr, "Cluster connection failed\n");
+                force_stop(1);
            }
            // Retry
            tfd->set_timer(st_cli.etcd_quick_timeout, false, [this](int timer_id)
--- a/src/osd_flush.cpp
+++ b/src/osd_flush.cpp
@@ -47,7 +47,8 @@ void osd_t::submit_pg_flush_ops(pg_t & pg)
        if (l.second.size() > 0)
        {
            fb->flush_ops++;
-            submit_flush_op(pg.pool_id, pg.pg_num, fb, true, l.first, l.second.size(), l.second.data());
+            if (!submit_flush_op(pg.pool_id, pg.pg_num, fb, true, l.first, l.second.size(), l.second.data()))
+                return;
        }
    }
    for (auto & l: fb->stable_lists)
@@ -55,7 +56,8 @@ void osd_t::submit_pg_flush_ops(pg_t & pg)
        if (l.second.size() > 0)
        {
            fb->flush_ops++;
-            submit_flush_op(pg.pool_id, pg.pg_num, fb, false, l.first, l.second.size(), l.second.data());
+            if (!submit_flush_op(pg.pool_id, pg.pg_num, fb, false, l.first, l.second.size(), l.second.data()))
+                return;
        }
    }
 }
@@ -160,7 +162,7 @@ void osd_t::handle_flush_op(bool rollback, pool_id_t pool_id, pg_num_t pg_num, p
    }
 }

-void osd_t::submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, bool rollback, osd_num_t peer_osd, int count, obj_ver_id *data)
+bool osd_t::submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t *fb, bool rollback, osd_num_t peer_osd, int count, obj_ver_id *data)
 {
    osd_op_t *op = new osd_op_t();
    // Copy buffer so it gets freed along with the operation
@@ -188,10 +190,8 @@ void osd_t::submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t
    else
    {
        // Peer
-        int peer_fd = msgr.osd_peer_fds[peer_osd];
        op->op_type = OSD_OP_OUT;
        op->iov.push_back(op->buf, count * sizeof(obj_ver_id));
-        op->peer_fd = peer_fd;
        op->req = (osd_any_op_t){
            .sec_stab = {
                .header = {
@@ -207,8 +207,21 @@ void osd_t::submit_flush_op(pool_id_t pool_id, pg_num_t pg_num, pg_flush_batch_t
            handle_flush_op(op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK, pool_id, pg_num, fb, peer_osd, op->reply.hdr.retval);
            delete op;
        };
-        msgr.outbox_push(op);
+        auto peer_fd_it = msgr.osd_peer_fds.find(peer_osd);
+        if (peer_fd_it != msgr.osd_peer_fds.end())
+        {
+            op->peer_fd = peer_fd_it->second;
+            msgr.outbox_push(op);
+        }
+        else
+        {
+            // Fail it immediately
+            op->reply.hdr.retval = -EPIPE;
+            op->callback(op);
+            return false;
+        }
    }
+    return true;
 }

 bool osd_t::pick_next_recovery(osd_recovery_op_t &op)
--- a/src/osd_peering.cpp
+++ b/src/osd_peering.cpp
@@ -29,8 +29,10 @@ void osd_t::handle_peers()
                    degraded_objects += p.second.degraded_objects.size();
                    if (p.second.state & PG_HAS_UNCLEAN)
                        peering_state = peering_state | OSD_FLUSHING_PGS;
-                    else if (p.second.state & PG_HAS_DEGRADED)
+                    else if (p.second.state & (PG_HAS_DEGRADED | PG_HAS_MISPLACED))
                        peering_state = peering_state | OSD_RECOVERING;
+                    ringloop->wakeup();
+                    return;
                }
                else
                {
@@ -340,7 +342,7 @@ void osd_t::submit_sync_and_list_subop(osd_num_t role_osd, pg_peering_state_t *p
    else
    {
        // Peer
-        auto & cl = msgr.clients.at(msgr.osd_peer_fds[role_osd]);
+        auto & cl = msgr.clients.at(msgr.osd_peer_fds.at(role_osd));
        osd_op_t *op = new osd_op_t();
        op->op_type = OSD_OP_OUT;
        op->peer_fd = cl->peer_fd;
@@ -394,7 +396,9 @@ void osd_t::submit_list_subop(osd_num_t role_osd, pg_peering_state_t *ps)
        {
            if (op->bs_op->retval < 0)
            {
-                throw std::runtime_error("local OP_LIST failed");
+                printf("Local OP_LIST failed: retval=%d\n", op->bs_op->retval);
+                force_stop(1);
+                return;
            }
            add_bs_subop_stats(op);
            printf(
@@ -419,7 +423,7 @@ void osd_t::submit_list_subop(osd_num_t role_osd, pg_peering_state_t *ps)
        // Peer
        osd_op_t *op = new osd_op_t();
        op->op_type = OSD_OP_OUT;
-        op->peer_fd = msgr.osd_peer_fds[role_osd];
+        op->peer_fd = msgr.osd_peer_fds.at(role_osd);
        op->req = (osd_any_op_t){
            .sec_list = {
                .header = {
--- a/src/osd_primary_chain.cpp
+++ b/src/osd_primary_chain.cpp
@@ -246,7 +246,6 @@ int osd_t::submit_bitmap_subops(osd_op_t *cur_op, pg_t & pg)
                // Send to a remote OSD
                osd_op_t *subop = op_data->subops+subop_idx;
                subop->op_type = OSD_OP_OUT;
-                subop->peer_fd = msgr.osd_peer_fds.at(subop_osd_num);
                // FIXME: Use the pre-allocated buffer
                subop->buf = malloc_or_die(sizeof(obj_ver_id)*(i+1-prev));
                subop->req = (osd_any_op_t){
@@ -287,7 +286,18 @@ int osd_t::submit_bitmap_subops(osd_op_t *cur_op, pg_t & pg)
                    }
                    handle_primary_subop(subop, cur_op);
                };
-                msgr.outbox_push(subop);
+                auto peer_fd_it = msgr.osd_peer_fds.find(subop_osd_num);
+                if (peer_fd_it != msgr.osd_peer_fds.end())
+                {
+                    subop->peer_fd = peer_fd_it->second;
+                    msgr.outbox_push(subop);
+                }
+                else
+                {
+                    // Fail it immediately
+                    subop->reply.hdr.retval = -EPIPE;
+                    subop->callback(subop);
+                }
                subop_idx++;
            }
            prev = i+1;
--- a/src/osd_primary_subops.cpp
+++ b/src/osd_primary_subops.cpp
@@ -182,7 +182,6 @@ int osd_t::submit_primary_subop_batch(int submit_type, inode_t inode, uint64_t o
            else
            {
                subop->op_type = OSD_OP_OUT;
-                subop->peer_fd = msgr.osd_peer_fds.at(role_osd_num);
                subop->bitmap = stripes[stripe_num].bmp_buf;
                subop->bitmap_len = clean_entry_bitmap_size;
                subop->req.sec_rw = {
@@ -225,7 +224,18 @@ int osd_t::submit_primary_subop_batch(int submit_type, inode_t inode, uint64_t o
                {
                    handle_primary_subop(subop, cur_op);
                };
-                msgr.outbox_push(subop);
+                auto peer_fd_it = msgr.osd_peer_fds.find(role_osd_num);
+                if (peer_fd_it != msgr.osd_peer_fds.end())
+                {
+                    subop->peer_fd = peer_fd_it->second;
+                    msgr.outbox_push(subop);
+                }
+                else
+                {
+                    // Fail it immediately
+                    subop->reply.hdr.retval = -EPIPE;
+                    subop->callback(subop);
+                }
            }
            i++;
        }
@@ -463,7 +473,6 @@ void osd_t::submit_primary_del_batch(osd_op_t *cur_op, obj_ver_osd_t *chunks_to_
        else
        {
            subops[i].op_type = OSD_OP_OUT;
-            subops[i].peer_fd = msgr.osd_peer_fds.at(chunk.osd_num);
            subops[i].req = (osd_any_op_t){ .sec_del = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
@@ -477,7 +486,18 @@ void osd_t::submit_primary_del_batch(osd_op_t *cur_op, obj_ver_osd_t *chunks_to_
            {
                handle_primary_subop(subop, cur_op);
            };
-            msgr.outbox_push(&subops[i]);
+            auto peer_fd_it = msgr.osd_peer_fds.find(chunk.osd_num);
+            if (peer_fd_it != msgr.osd_peer_fds.end())
+            {
+                subops[i].peer_fd = peer_fd_it->second;
+                msgr.outbox_push(&subops[i]);
+            }
+            else
+            {
+                // Fail it immediately
+                subops[i].reply.hdr.retval = -EPIPE;
+                subops[i].callback(&subops[i]);
+            }
        }
    }
 }
@@ -567,7 +587,6 @@ void osd_t::submit_primary_stab_subops(osd_op_t *cur_op)
        else
        {
            subops[i].op_type = OSD_OP_OUT;
-            subops[i].peer_fd = msgr.osd_peer_fds.at(stab_osd.osd_num);
            subops[i].req = (osd_any_op_t){ .sec_stab = {
                .header = {
                    .magic = SECONDARY_OSD_OP_MAGIC,
@@ -581,7 +600,18 @@ void osd_t::submit_primary_stab_subops(osd_op_t *cur_op)
            {
                handle_primary_subop(subop, cur_op);
            };
-            msgr.outbox_push(&subops[i]);
+            auto peer_fd_it = msgr.osd_peer_fds.find(stab_osd.osd_num);
+            if (peer_fd_it != msgr.osd_peer_fds.end())
+            {
+                subops[i].peer_fd = peer_fd_it->second;
+                msgr.outbox_push(&subops[i]);
+            }
+            else
+            {
+                // Fail it immediately
+                subops[i].reply.hdr.retval = -EPIPE;
+                subops[i].callback(&subops[i]);
+            }
        }
    }
 }
--- a/src/osd_rmw.h
+++ b/src/osd_rmw.h
@@ -8,7 +8,7 @@
 #include "osd_id.h"

 #ifndef MEM_ALIGNMENT
-#define MEM_ALIGNMENT 512
+#define MEM_ALIGNMENT 4096
 #endif

 struct buf_len_t
--- a/src/osd_test.cpp
+++ b/src/osd_test.cpp
@@ -134,14 +134,14 @@ int main(int narg, char *args[])

 int connect_osd(const char *osd_address, int osd_port)
 {
-    struct sockaddr addr;
+    struct sockaddr_storage addr;
    if (!string_to_addr(osd_address, 0, osd_port, &addr))
    {
        fprintf(stderr, "server address: %s is not valid\n", osd_address);
        return -1;
    }

-    int connect_fd = socket(addr.sa_family, SOCK_STREAM, 0);
+    int connect_fd = socket(addr.ss_family, SOCK_STREAM, 0);
    if (connect_fd < 0)
    {
        perror("socket");
--- a/src/ringloop.cpp
+++ b/src/ringloop.cpp
@@ -112,3 +112,17 @@ void ring_loop_t::restore(unsigned sqe_tail)
    }
    ring.sq.sqe_tail = sqe_tail;
 }
+
+int ring_loop_t::sqes_left()
+{
+    struct io_uring_sq *sq = &ring.sq;
+    unsigned int head = io_uring_smp_load_acquire(sq->khead);
+    unsigned int next = sq->sqe_tail + 1;
+    int left = *sq->kring_entries - (next - head);
+    if (left > free_ring_data_ptr)
+    {
+        // return min(sqes left, ring_datas left)
+        return free_ring_data_ptr;
+    }
+    return left;
+}
--- a/src/ringloop.h
+++ b/src/ringloop.h
@@ -17,15 +17,12 @@

 static inline void my_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd, const void *addr, unsigned len, off_t offset)
 {
-    sqe->opcode = op;
-    sqe->flags = 0;
-    sqe->ioprio = 0;
-    sqe->fd = fd;
-    sqe->off = offset;
-    sqe->addr = (unsigned long) addr;
-    sqe->len = len;
-    sqe->rw_flags = 0;
-    sqe->__pad2[0] = sqe->__pad2[1] = sqe->__pad2[2] = 0;
+    // Prepare a read/write operation without clearing user_data
+    // Very recently, 22 Dec 2021, liburing finally got this change too (8ecd3fd959634df81d66af8b3a69c16202a014e8)
+    // But all versions prior to it (sadly) clear user_data
+    __u64 user_data = sqe->user_data;
+    io_uring_prep_rw(op, sqe, fd, addr, len, offset);
+    sqe->user_data = user_data;
 }

 static inline void my_uring_prep_readv(struct io_uring_sqe *sqe, int fd, const struct iovec *iovecs, unsigned nr_vecs, off_t offset)
@@ -172,6 +169,7 @@ public:
        struct io_uring_cqe *cqe;
        return io_uring_wait_cqe(&ring, &cqe);
    }
+    int sqes_left();
    inline unsigned space_left()
    {
        return free_ring_data_ptr;
--- a/src/stub_bench.cpp
+++ b/src/stub_bench.cpp
@@ -67,14 +67,14 @@ int main(int narg, char *args[])

 int connect_stub(const char *server_address, int server_port)
 {
-    struct sockaddr addr;
+    struct sockaddr_storage addr;
    if (!string_to_addr(server_address, 0, server_port, &addr))
    {
        fprintf(stderr, "server address: %s is not valid\n", server_address);
        return -1;
    }

-    int connect_fd = socket(addr.sa_family, SOCK_STREAM, 0);
+    int connect_fd = socket(addr.ss_family, SOCK_STREAM, 0);
    if (connect_fd < 0)
    {
        perror("socket");
--- a/src/stub_osd.cpp
+++ b/src/stub_osd.cpp
@@ -41,21 +41,19 @@
 #include "rw_blocking.h"
 #include "osd_ops.h"

-int bind_stub(std::string bind_address, int bind_port);
-
 void run_stub(int peer_fd);

 int main(int narg, char *args[])
 {
-    int listen_fd = bind_stub("0.0.0.0", 11203);
+    int listen_fd = create_and_bind_socket("0.0.0.0", 11203, 128, NULL);
    // Accept new connections
-    sockaddr addr;
+    sockaddr_storage addr;
    socklen_t peer_addr_size = sizeof(addr);
    int peer_fd;
    while (1)
    {
        printf("stub_osd: waiting for 1 client\n");
-        peer_fd = accept(listen_fd, &addr, &peer_addr_size);
+        peer_fd = accept(listen_fd, (sockaddr*)&addr, &peer_addr_size);
        if (peer_fd == -1)
        {
            if (errno == EAGAIN)
@@ -76,39 +74,6 @@ int main(int narg, char *args[])
    return 0;
 }

-int bind_stub(std::string bind_address, int bind_port)
-{
-    int listen_backlog = 128;
-
-    sockaddr addr;
-    if (!string_to_addr(bind_address, 0, bind_port, &addr))
-    {
-        throw std::runtime_error("bind address "+bind_address+" is not valid");
-    }
-
-    int listen_fd = socket(addr.sa_family, SOCK_STREAM, 0);
-    if (listen_fd < 0)
-    {
-        throw std::runtime_error(std::string("socket: ") + strerror(errno));
-    }
-    int enable = 1;
-    setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
-
-    if (bind(listen_fd, &addr, sizeof(addr)) < 0)
-    {
-        close(listen_fd);
-        throw std::runtime_error(std::string("bind: ") + strerror(errno));
-    }
-
-    if (listen(listen_fd, listen_backlog) < 0)
-    {
-        close(listen_fd);
-        throw std::runtime_error(std::string("listen: ") + strerror(errno));
-    }
-
-    return listen_fd;
-}
-
 void run_stub(int peer_fd)
 {
    osd_any_op_t op;
--- a/src/stub_uring_osd.cpp
+++ b/src/stub_uring_osd.cpp
@@ -25,8 +25,6 @@
 #include "epoll_manager.h"
 #include "messenger.h"

-int bind_stub(std::string bind_address, int bind_port);
-
 void stub_exec_op(osd_messenger_t *msgr, osd_op_t *op);

 int main(int narg, char *args[])
@@ -43,7 +41,8 @@ int main(int narg, char *args[])
    json11::Json config = json11::Json::object { { "log_level", 1 } };
    msgr->parse_config(config);
    // Accept new connections
-    int listen_fd = bind_stub("0.0.0.0", 11203);
+    int listen_fd = create_and_bind_socket("0.0.0.0", 11203, 128, NULL);
+    fcntl(listen_fd, F_SETFL, fcntl(listen_fd, F_GETFL, 0) | O_NONBLOCK);
    epmgr->set_fd_handler(listen_fd, false, [listen_fd, msgr](int fd, int events)
    {
        msgr->accept_connections(listen_fd);
@@ -67,41 +66,6 @@ int main(int narg, char *args[])
    return 0;
 }

-int bind_stub(std::string bind_address, int bind_port)
-{
-    int listen_backlog = 128;
-
-    sockaddr addr;
-    if (!string_to_addr(bind_address, 0, bind_port, &addr))
-    {
-        throw std::runtime_error("bind address "+bind_address+" is not valid");
-    }
-
-    int listen_fd = socket(addr.sa_family, SOCK_STREAM, 0);
-    if (listen_fd < 0)
-    {
-        throw std::runtime_error(std::string("socket: ") + strerror(errno));
-    }
-    int enable = 1;
-    setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable));
-
-    if (bind(listen_fd, &addr, sizeof(addr)) < 0)
-    {
-        close(listen_fd);
-        throw std::runtime_error(std::string("bind: ") + strerror(errno));
-    }
-
-    if (listen(listen_fd, listen_backlog) < 0)
-    {
-        close(listen_fd);
-        throw std::runtime_error(std::string("listen: ") + strerror(errno));
-    }
-
-    fcntl(listen_fd, F_SETFL, fcntl(listen_fd, F_GETFL, 0) | O_NONBLOCK);
-
-    return listen_fd;
-}
-
 void stub_exec_op(osd_messenger_t *msgr, osd_op_t *op)
 {
    op->reply.hdr.magic = SECONDARY_OSD_REPLY_MAGIC;
--- a/src/vitastor.pc.in
+++ b/src/vitastor.pc.in
@@ -6,7 +6,7 @@ includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@

 Name: Vitastor
 Description: Vitastor client library
-Version: 0.6.12
+Version: 0.6.15
 Libs: -L${libdir} -lvitastor_client
 Cflags: -I${includedir}
Author	SHA1	Message	Date
Vitaliy Filippov	85298ddae2	Release 0.6.15 - Make peering much faster in medium to large clusters - Fix a reenterability issue which could rarely lead to peering process hangs	2022-03-06 19:16:34 +03:00
Vitaliy Filippov	e23296a327	Rename cli_rm -> cli_rm_data, cli_snap_rm -> cli_rm	2022-02-24 14:34:14 +03:00
Vitaliy Filippov	839ec9e6e0	Shard clean_db by PGs to speedup listings	2022-02-20 00:21:24 +03:00
Vitaliy Filippov	7cbfdff41a	Replace some throws with force_stop	2022-02-20 00:21:19 +03:00
Vitaliy Filippov	951272f27f	Try to process PG one after another	2022-02-19 19:25:55 +03:00
Vitaliy Filippov	a3fb1d4c98	Fix reenterability around set_timer	2022-02-19 18:28:12 +03:00
Vitaliy Filippov	88402e6eb6	Move next_request to run_cb_and_clear	2022-02-19 16:59:03 +03:00
Vitaliy Filippov	390239c51b	Don't terminate HTTP requests with timeouts if response is already available in the socket	2022-02-19 13:37:12 +03:00
Vitaliy Filippov	b7b2adfa32	Fix http client not continuing requests in case of failure to connect	2022-02-19 13:36:26 +03:00
Vitaliy Filippov	36c276358b	Attempt to fix "head-of-line blocking" by LIST operations	2022-02-18 01:31:45 +03:00
Vitaliy Filippov	117d6f0612	Release 0.6.14 - Fix IPv6 address parsing - Fix "cannot read bytes of undefined" in the monitor on a fresh DB - Fix possible hangs of read requests on OSD restarts without immediate_commit=all mode - Fix OSDs skipping misplaced recovery in some cases - Fix OSDs possibly dying with "map::at" errors when other OSDs are stopped - Fix division by zero in ls if all pool OSDs are down	2022-02-17 14:43:44 +03:00
Vitaliy Filippov	7d79c58095	Use the larger sockaddr_storage structure	2022-02-12 11:22:56 +03:00
Vitaliy Filippov	46d2bc100f	Add some tolerance to stat calculation so it does not fail on a fresh DB	2022-02-11 16:37:16 +03:00
Vitaliy Filippov	732e2804e9	Fix operation dependency counter underflow for reads without immediate_commit=all mode	2022-02-11 10:54:11 +03:00
Vitaliy Filippov	abaec2008c	Fix OSDs missing misplaced recovery	2022-02-11 01:00:24 +03:00
Vitaliy Filippov	8129d238a4	Different fio versions have different types for xfer_buflen, but Vitastor anyway does not support 128-bit offsets	2022-02-10 01:21:04 +03:00
Vitaliy Filippov	61ebed144a	Fix OSDs possibly dying with "map::at" errors when other OSDs are stopped	2022-02-09 10:35:29 +03:00
Vitaliy Filippov	9d3ba113aa	Extract bind socket code into a utility function	2022-02-06 00:39:52 +03:00
Vitaliy Filippov	9788045dc9	Fix division by zero in ls if all pool OSDs are down	2022-02-05 17:03:37 +03:00
Vitaliy Filippov	d6b0d29af6	4k MEM_ALIGNMENT	2022-02-05 17:03:37 +03:00
Vitaliy Filippov	36f352f06f	Release 0.6.13 - Fix client hangs possible on OSD restarts (bug affected versions from 0.5.11) - Fix "Assertion `sqe != NULL' failed" io_uring-related crashes possible on some kernels (0.6.11 increased probability of this bug) - Fix timeout=0 in NBD proxy - Fix build under centos 7	2022-02-03 01:50:30 +03:00
Vitaliy Filippov	318cc463c2	Fix warnings	2022-02-03 01:50:30 +03:00
Vitaliy Filippov	145e5cfb86	MCL_ONFAULT is not available under centos 7	2022-02-03 01:42:19 +03:00
Vitaliy Filippov	73ae578981	Add osd_memlock option	2022-02-02 01:40:22 +03:00
Vitaliy Filippov	20ee4ed758	Update some parameter docs	2022-02-01 22:46:13 +03:00
Vitaliy Filippov	63de79d1b2	Change > to \| to preserve newlines	2022-02-01 22:45:12 +03:00
Vitaliy Filippov	f712967079	And one more sqe starvation fix	2022-02-01 02:50:16 +03:00
Vitaliy Filippov	df0cd85352	Fix another part of the "async sqe clear" bug (followup to `d9857a5340`)	2022-02-01 01:14:56 +03:00
Vitaliy Filippov	ebaf4d7a72	Fix compatibility with fio 3.28+	2022-01-31 23:39:14 +03:00
Vitaliy Filippov	d4bc10542c	Fix compatibility with liburing >= 2.1 where it only has __pad2[2]	2022-01-31 22:49:40 +03:00
Vitaliy Filippov	140309620a	Free recv_buf in nbd_proxy	2022-01-31 20:37:58 +03:00
Vitaliy Filippov	0a610ee943	Destroy the client after completing CLI command	2022-01-31 18:27:04 +03:00
Vitaliy Filippov	f3ce166064	Do not print nan% in df when a pool has no available OSDs	2022-01-31 18:23:57 +03:00
Vitaliy Filippov	717d303370	Handle get_sqe failures, don't die with "will fall out of sync" in epoll_manager Problem is that in recent kernels io_uring may return completions BEFORE clearing the submission queue. I.e. for example its capacity is 512, there were 512 requests, one of them completed, so when the request completion is processed the queue "should have" 1 free slot. But sometimes it doesn't because io_uring doesn't always clear the submission queue before sending CQE :-/	2022-01-31 02:52:20 +03:00
Vitaliy Filippov	d9857a5340	Check for SQEs, not for completions Should finally fix Assertion `sqe != NULL' failed introduced after journaling refactor in 0.6.11...	2022-01-31 02:19:10 +03:00
Vitaliy Filippov	eb5d9153e8	Fix build under centos 7	2022-01-30 20:29:44 +03:00
Vitaliy Filippov	ae6d1ed1d5	Remove completed items	2022-01-30 20:20:06 +03:00
Vitaliy Filippov	d123e58ea3	Fix yaml syntax - remove ` in default	2022-01-29 02:08:48 +03:00
Vitaliy Filippov	d9869d8116	Add parameter documentation	2022-01-28 02:45:54 +03:00
Vitaliy Filippov	4047ca606f	Add missing cancel_op(currently being read op) when stopping a client Fixes client hangs possible after stopping & restarting an osd. Hangs happened when a connection was closed in the middle of reading a READ operation reply from the network. In this case the operation being read was in read_op and the client didn't free it when closing the connection. Test case for msgr_read.cpp: - Partially read reply for a READ operation - stop_client() - Check that the READ operation returns EPIPE The bug was actually introduced in 0.5.11.	2022-01-28 01:53:52 +03:00
Vitaliy Filippov	218e294e9c	> 0, of course	2022-01-24 13:36:09 +03:00