libfio_fileserver/README.md

libfio_fileserver

This is a loadable engine for fio to test something similar to the file server access pattern where a number of files is sharded over several levels of subdirectories.

Building

• Clone this repository
• Clone or symlink the source code directory for your exact fio version in ./fio subdirectory
• Install g++
• Run make

Usage

fio -name=test -ioengine=./libfio_fileserver.so -directory=/home/bench \
    -chunk_size=256k -size=10G -direct=1 [-dir_levels=2] [-subdirs_per_dir=64] \
    -bs=256k -rw=randwrite [-fsync_on_close=1] [-sync=1] [-numjobs=16 -group_reporting]

Notes:

• direct=1 is optional, but without it you'll be benchmarking the page cache
• bs=256k must be less or equal to chunk_size
• fsync=N is supported, but it only fsyncs a random file
• reads return error when encountering a non-existing file
• You can also use various distribution parameters (zipf, etc)
• I/O is done using synchronous syscalls, thus iodepth is not supported

Because of the synchronous syscalls it's slightly tricky to use parallelism correctly. So, for example, to fill the directory with 262144 4k files, run:

fio -thread -name=test -direct=1 -ioengine=./libfio_fileserver.so -fsync_on_close=1 \
    -directory=/home/bench -chunk_size=4k -size=1G -bs=4k -rw=write:508k \
    -numjobs=128 -offset_increment=4k -group_reporting

License & Author

• Author: Vitaliy Filippov vitalif[at]yourcmc.ru, 2020
• License: GNU GPL v2.0 or later version