Mark, As we discussed in today's meeting , I ran 100% RR with the following fio profile on a single image of 4TB. Did precondition the entire image with 1M seq write. I have total of 16 OSDs over 2 nodes. [global] ioengine=rbd clientname=admin pool=recovery_test rbdname=recovery_image invalidate=0 # mandatory rw=randread bs=4k direct=1 time_based runtime=30m numjobs=8 group_reporting [rbd_iodepth32] iodepth=128 Here is the ceph.conf option I used for Bluestore. osd_op_num_threads_per_shard = 2 osd_op_num_shards = 25 bluestore_rocksdb_options = "max_write_buffer_number=16,min_write_buffer_number_to_merge=16,recycle_log_file_num=16,compaction_threads=32,flusher_threads=4, max_background_compactions=32,max_background_flushes=8,max_bytes_for_level_base=5368709120,write_buffer_size=83886080,level0_file_num_compaction_trigger=4,level0_slowdown_writes_trigger=400,level0_stop_writes_trigger=800" rocksdb_cache_size = 4294967296 #bluestore_min_alloc_size = 16384 bluestore_min_alloc_size = 4096 bluestore_csum = false bluestore_csum_type = none bluestore_bluefs_buffered_io = false bluestore_max_ops = 30000 bluestore_max_bytes = 629145600 Here is the output I got. rbd_iodepth32: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=rbd, iodepth=128 ... fio-2.1.11 Starting 8 processes rbd engine: RBD version: 0.1.10 rbd engine: RBD version: 0.1.10 rbd engine: RBD version: 0.1.10 rbd engine: RBD version: 0.1.10 rbd engine: RBD version: 0.1.10 rbd engine: RBD version: 0.1.10 rbd engine: RBD version: 0.1.10 rbd engine: RBD version: 0.1.10 ^Cbs: 8 (f=8): [r(8)] [9.4% done] [179.5MB/0KB/0KB /s] [45.1K/0/0 iops] [eta 27m:12s] fio: terminating on signal 2 rbd_iodepth32: (groupid=0, jobs=8): err= 0: pid=1266211: Thu Jul 14 09:42:28 2016 read : io=95898MB, bw=583425KB/s, iops=145856, runt=168316msec slat (usec): min=0, max=13967, avg= 4.56, stdev=38.79 clat (usec): min=15, max=1949.3K, avg=6941.73, stdev=16018.84 lat (usec): min=225, max=1949.3K, avg=6946.30, stdev=16018.92 clat percentiles (usec): | 1.00th=[ 876], 5.00th=[ 2024], 10.00th=[ 2672], 20.00th=[ 3312], | 30.00th=[ 3824], 40.00th=[ 4320], 50.00th=[ 5024], 60.00th=[ 5920], | 70.00th=[ 7072], 80.00th=[ 8768], 90.00th=[11840], 95.00th=[15040], | 99.00th=[22400], 99.50th=[27264], 99.90th=[248832], 99.95th=[366592], | 99.99th=[602112] I was getting > 600MB/s before memory started swapping for me and the fio output came down. I never tested Bluestore read before, but, it is definitely lower than Filestore for me. But, it is far better than you are getting it seems (?). Do you mind trying with the above ceph.conf option as well ? My ceph version : ceph version 11.0.0-536-g8df0c5b (8df0c5bcd90d80e9b309b2a9007b778f7b829edf) Thanks & Regards Somnath PLEASE NOTE: The information contained in this electronic mail message is intended only for the use of the designated recipient(s) named above. If the reader of this message is not the intended recipient, you are hereby notified that you have received this message in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify the sender by telephone or e-mail (as shown above) immediately and destroy any and all copies of this message in your possession (whether hard copies or electronically stored copies). -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html