diff --git a/blockstore_flush.h b/blockstore_flush.h
index 294bd0a5..740f3fa8 100644
--- a/blockstore_flush.h
+++ b/blockstore_flush.h
@@ -46,7 +46,7 @@ class journal_flusher_co
     std::function<void(ring_data_t*)> simple_callback_r, simple_callback_w;
 
     bool skip_copy, has_delete, has_empty;
-    spp::sparse_hash_map<object_id, clean_entry>::iterator clean_it;
+    blockstore_clean_db_t::iterator clean_it;
     std::vector<copy_buffer_t> v;
     std::vector<copy_buffer_t>::iterator it;
     int copy_count;
diff --git a/blockstore_impl.h b/blockstore_impl.h
index 874e7e0d..c4c81cb2 100644
--- a/blockstore_impl.h
+++ b/blockstore_impl.h
@@ -16,7 +16,7 @@
 #include <deque>
 #include <new>
 
-#include "sparsepp/sparsepp/spp.h"
+#include "cpp-btree/btree_map.h"
 
 #include "allocator.h"
 
@@ -164,6 +164,10 @@ struct blockstore_op_private_t
     int sync_state, prev_sync_count;
 };
 
+// https://github.com/algorithm-ninja/cpp-btree
+// https://github.com/greg7mdp/sparsepp/ was used previously, but it was TERRIBLY slow after resizing
+// with sparsepp, random reads dropped to ~700 iops very fast with just as much as ~32k objects in the DB
+typedef btree::btree_map<object_id, clean_entry> blockstore_clean_db_t;
 typedef std::map<obj_ver_id, dirty_entry> blockstore_dirty_db_t;
 
 #include "blockstore_init.h"
@@ -198,8 +202,7 @@ class blockstore_impl_t
 
     struct ring_consumer_t ring_consumer;
 
-    // Another option is https://github.com/algorithm-ninja/cpp-btree
-    spp::sparse_hash_map<object_id, clean_entry> clean_db;
+    blockstore_clean_db_t clean_db;
     uint8_t *clean_bitmap = NULL;
     blockstore_dirty_db_t dirty_db;
     std::list<blockstore_op_t*> submit_queue; // FIXME: funny thing is that vector is better here
diff --git a/osd.h b/osd.h
index 7784db9f..97c735f2 100644
--- a/osd.h
+++ b/osd.h
@@ -19,8 +19,6 @@
 #include "osd_ops.h"
 #include "osd_peering_pg.h"
 
-#include "sparsepp/sparsepp/spp.h"
-
 #define OSD_OP_IN 0
 #define OSD_OP_OUT 1
 
diff --git a/osd_peering_pg.cpp b/osd_peering_pg.cpp
index 0db329a2..4babecf0 100644
--- a/osd_peering_pg.cpp
+++ b/osd_peering_pg.cpp
@@ -93,7 +93,7 @@ void pg_t::remember_object(pg_obj_state_check_t &st, std::vector<obj_ver_role> &
         }
         if (state & (OBJ_NEEDS_ROLLBACK | OBJ_NEEDS_STABLE))
         {
-            spp::sparse_hash_map<obj_piece_id_t, obj_piece_ver_t> pieces;
+            std::unordered_map<obj_piece_id_t, obj_piece_ver_t> pieces;
             for (int i = st.obj_start; i < st.obj_end; i++)
             {
                 auto & pcs = pieces[(obj_piece_id_t){ .oid = all[i].oid, .osd_num = all[i].osd_num }];
diff --git a/osd_peering_pg.h b/osd_peering_pg.h
index 62ba3d6b..571d9edc 100644
--- a/osd_peering_pg.h
+++ b/osd_peering_pg.h
@@ -1,12 +1,13 @@
 #include <map>
+#include <unordered_map>
 #include <vector>
 #include <algorithm>
 
+#include "cpp-btree/btree_map.h"
+
 #include "object_id.h"
 #include "osd_ops.h"
 
-#include "sparsepp/sparsepp/spp.h"
-
 // Placement group states
 // Exactly one of these:
 #define PG_OFFLINE (1<<0)
@@ -64,8 +65,8 @@ struct osd_op_t;
 struct pg_peering_state_t
 {
     // osd_num -> list result
-    spp::sparse_hash_map<osd_num_t, osd_op_t*> list_ops;
-    spp::sparse_hash_map<osd_num_t, pg_list_result_t> list_results;
+    std::unordered_map<osd_num_t, osd_op_t*> list_ops;
+    std::unordered_map<osd_num_t, pg_list_result_t> list_results;
     int list_done = 0;
 };
 
@@ -122,9 +123,9 @@ struct pg_t
     // it may consume up to ~ (raw storage / object size) * 24 bytes in the worst case scenario
     // which is up to ~192 MB per 1 TB in the worst case scenario
     std::map<pg_osd_set_t, pg_osd_set_state_t> state_dict;
-    spp::sparse_hash_map<object_id, pg_osd_set_state_t*> obj_states;
+    btree::btree_map<object_id, pg_osd_set_state_t*> obj_states;
     std::map<obj_piece_id_t, obj_stab_action_t> obj_stab_actions;
-    spp::sparse_hash_map<object_id, uint64_t> ver_override;
+    btree::btree_map<object_id, uint64_t> ver_override;
     pg_peering_state_t *peering_state = NULL;
 
     std::multimap<object_id, osd_op_t*> write_queue;