Somnath, Mark
I have a question and some comments w.r.t. memory swapping.
What's amount of RAM do you have at your nodes? How many of it is taken
by OSDs?
I can see that each BlueStore OSD may occupy
bluestore_buffer_cache_size * osd_op_num_shards = 512M * 5 = 2.5G (by
default) for buffer cache.
Hence in Somnath's environment one might expect up to 20G taken for the
cache. Does that estimation correlate with the real life?
Thanks,
Igor
On 14.07.2016 19:50, Somnath Roy wrote:
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
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