I did some more tests :fio on a raw RBD volume (4K, numjob=32, QD=1) gives me around 3000 IOPSI also tuned xfs mount options on client (I realized I didn't do that already) and with "largeio,inode64,swalloc,logbufs=8,logbsize=256k,attr2,auto,nodev,noatime,nodiratime" I get better performance :4k-32-1-randwrite-libaio: (groupid=0, jobs=32): err= 0: pid=26793: Thu Dec 3 10:45:55 2015write: io=1685.3MB, bw=5720.1KB/s, iops=1430, runt=301652msecslat (usec): min=5, max=1620, avg=41.61, stdev=25.82clat (msec): min=1, max=4141, avg=14.61, stdev=112.55lat (msec): min=1, max=4141, avg=14.65, stdev=112.55clat percentiles (msec):| 1.00th=[ 3], 5.00th=[ 4], 10.00th=[ 4], 20.00th=[ 4],| 30.00th=[ 4], 40.00th=[ 5], 50.00th=[ 5], 60.00th=[ 5],| 70.00th=[ 5], 80.00th=[ 6], 90.00th=[ 7], 95.00th=[ 7],| 99.00th=[ 227], 99.50th=[ 717], 99.90th=[ 1844], 99.95th=[ 2245],| 99.99th=[ 3097]So, more than 50% improvement but it actually varies quite a lot between tests (sometimes I get a bit more than 1000). If I run the test fo 30 minutes it drops to 900 IOPS.As you suggested I also filled a volume with zeros (dd if=/dev/zero of=/dev/rbd1 bs=1M) and then ran fio on the raw device, I didn't see a lot of improvement.If I run fio test directly on block devices I seem to saturate the spinners, [1] is a graph of IO load on one of the OSD host.[2] is the same OSD graph but when the test is done on a device mounted and formatted with XFS on the client.If I get half of the IOPS on the XFS volume because of the journal, shouldn't I get the same amount of IOPS on the backend ?[3] shows what happen if I run the test for 30 minutes.During the fio tests on the raw device, load average on the OSD servers increases up to 13/14 and I get a bit of iowait (I guess because the OSD are busy)During the fio tests on the raw device, load average on the OSD servers peaks at the beginning and decreases to 5/6, but goes trough the roof on the client.Scheduler is deadline for all the drives, I didn't try to change it yet.What I don't understand, even with your explanations, are the rados results. From what I understand it performs at the RADOS level and thus should not be impacted by client filesystem.Given the results above I guess you are right and this has to do with the client filesystem.The cluster will be used for backups, write IO size during backups is around 150/200K (I guess mostly sequential) and I am looking for the highest bandwith and parallelization.@Nick, I will try to create a new stand alone replicated pool.--On Thu, Dec 3, 2015 at 1:30 PM, Nick Fisk <nick@xxxxxxxxxx> wrote:Couple of things to check
1. Can you create just a normal non cached pool and test performance to rule out any funnies going on there.
2. Can you also run something like iostat during the benchmarks and see if it looks like all your disks are getting saturated.
_____________________________________________
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Adrien Gillard
Sent: 02 December 2015 21:33
To: ceph-users@xxxxxxxx
Subject: New cluster performance analysis
Hi everyone,
I am currently testing our new cluster and I would like some feedback on the numbers I am getting.
For the hardware :
7 x OSD : 2 x Intel 2640v3 (8x2.6GHz), 64B RAM, 2x10Gbits LACP for public net., 2x10Gbits LACP for cluster net., MTU 9000
1 x MON : 2 x Intel 2630L (6x2GHz), 32GB RAM and Intel DC SSD, 2x10Gbits LACP for public net., MTU 9000
2 x MON : VMs (8 cores, 8GB RAM), backed by SSD
Journals are 20GB partitions on SSD
The system is CentOS 7.1 with stock kernel (3.10.0-229.20.1.el7.x86_64). No particular system optimizations.
Ceph is Infernalis from Ceph repository : ceph version 9.2.0 (bb2ecea240f3a1d525bcb35670cb07bd1f0ca299)
[cephadm@cph-adm-01 ~/scripts]$ ceph -s
cluster 259f65a3-d6c8-4c90-a9c2-71d4c3c55cce
health HEALTH_OK
monmap e1: 3 mons at {clb-cph-frpar1-mon-02=x.x.x.2:6789/0,clb-cph-frpar2-mon-01=x.x.x.1:6789/0,clb-cph-frpar2-mon-03=x.x.x.3:6789/0}
election epoch 62, quorum 0,1,2 clb-cph-frpar2-mon-01,clb-cph-frpar1-mon-02,clb-cph-frpar2-mon-03
osdmap e844: 84 osds: 84 up, 84 in
flags sortbitwise
pgmap v111655: 3136 pgs, 3 pools, 3166 GB data, 19220 kobjects
8308 GB used, 297 TB / 305 TB avail
3136 active+clean
My ceph.conf :
[global]
fsid = 259f65a3-d6c8-4c90-a9c2-71d4c3c55cce
mon_initial_members = clb-cph-frpar2-mon-01, clb-cph-frpar1-mon-02, clb-cph-frpar2-mon-03
mon_host = x.x.x.1,x.x.x.2,x.x.x.3
auth_cluster_required = cephx
auth_service_required = cephx
auth_client_required = cephx
filestore_xattr_use_omap = true
public network = 10.25.25.0/24
cluster network = 10.25.26.0/24
debug_lockdep = 0/0
debug_context = 0/0
debug_crush = 0/0
debug_buffer = 0/0
debug_timer = 0/0
debug_filer = 0/0
debug_objecter = 0/0
debug_rados = 0/0
debug_rbd = 0/0
debug_journaler = 0/0
debug_objectcatcher = 0/0
debug_client = 0/0
debug_osd = 0/0
debug_optracker = 0/0
debug_objclass = 0/0
debug_filestore = 0/0
debug_journal = 0/0
debug_ms = 0/0
debug_monc = 0/0
debug_tp = 0/0
debug_auth = 0/0
debug_finisher = 0/0
debug_heartbeatmap = 0/0
debug_perfcounter = 0/0
debug_asok = 0/0
debug_throttle = 0/0
debug_mon = 0/0
debug_paxos = 0/0
debug_rgw = 0/0
[osd]
osd journal size = 0
osd mount options xfs = "rw,noatime,inode64,logbufs=8,logbsize=256k"
filestore min sync interval = 5
filestore max sync interval = 15
filestore queue max ops = 2048
filestore queue max bytes = 1048576000
filestore queue committing max ops = 4096
filestore queue committing max bytes = 1048576000
filestore op thread = 32
filestore journal writeahead = true
filestore merge threshold = 40
filestore split multiple = 8
journal max write bytes = 1048576000
journal max write entries = 4096
journal queue max ops = 8092
journal queue max bytes = 1048576000
osd max write size = 512
osd op threads = 16
osd disk threads = 2
osd op num threads per shard = 3
osd op num shards = 10
osd map cache size = 1024
osd max backfills = 1
osd recovery max active = 2
I have set up 2 pools : one for cache with 3x replication in front of an EC pool. At the moment I am only interested in the cache pool, so no promotions/flushes/evictions happen.
(I know, I am using the same set of OSD for hot and cold data, but in my use case they should not be used at the same time.)
I am accessing the cluster via RBD volumes mapped with the kernel module on CentOS 7.1. These volumes are formatted in XFS on the clients.
The journal SSDs seem to perform quite well according to the results of Sebastien Han’s benchmark suggestion (they are Sandisk) :
write: io=22336MB, bw=381194KB/s, iops=95298, runt= 60001msec (this is for numjob=10)
Here are the rados bench tests :
rados bench -p rbdcache 120 write -b 4K -t 32 --no-cleanup
Total time run: 121.410763
Total writes made: 65357
Write size: 4096
Bandwidth (MB/sec): 2.1
Stddev Bandwidth: 0.597
Max bandwidth (MB/sec): 3.89
Min bandwidth (MB/sec): 0.00781
Average IOPS: 538
Stddev IOPS: 152
Max IOPS: 995
Min IOPS: 2
Average Latency: 0.0594
Stddev Latency: 0.18
Max latency: 2.82
Min latency: 0.00494
And the results of the fio test with the following parameters :
[global]
size=8G
runtime=300
ioengine=libaio
invalidate=1
direct=1
sync=1
fsync=1
numjobs=32
rw=randwrite
name=4k-32-1-randwrite-libaio
blocksize=4K
iodepth=1
directory=/mnt/rbd
group_reporting=1
4k-32-1-randwrite-libaio: (groupid=0, jobs=32): err= 0: pid=20442: Wed Dec 2 21:38:30 2015
write: io=992.11MB, bw=3389.3KB/s, iops=847, runt=300011msec
slat (usec): min=5, max=4726, avg=40.32, stdev=41.28
clat (msec): min=2, max=2208, avg=19.35, stdev=74.34
lat (msec): min=2, max=2208, avg=19.39, stdev=74.34
clat percentiles (msec):
| 1.00th=[ 3], 5.00th=[ 4], 10.00th=[ 4], 20.00th=[ 4],
| 30.00th=[ 4], 40.00th=[ 5], 50.00th=[ 5], 60.00th=[ 5],
| 70.00th=[ 6], 80.00th=[ 7], 90.00th=[ 38], 95.00th=[ 63],
| 99.00th=[ 322], 99.50th=[ 570], 99.90th=[ 1074], 99.95th=[ 1221],
| 99.99th=[ 1532]
bw (KB /s): min= 1, max= 448, per=3.64%, avg=123.48, stdev=102.09
lat (msec) : 4=30.30%, 10=51.27%, 20=1.71%, 50=9.91%, 100=4.03%
lat (msec) : 250=1.55%, 500=0.62%, 750=0.33%, 1000=0.16%
cpu : usr=0.09%, sys=0.25%, ctx=963114, majf=0, minf=928
IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
issued : total=r=0/w=254206/d=0, short=r=0/w=0/d=0, drop=r=0/w=0/d=0
latency : target=0, window=0, percentile=100.00%, depth=1
Run status group 0 (all jobs):
WRITE: io=992.11MB, aggrb=3389KB/s, minb=3389KB/s, maxb=3389KB/s, mint=300011msec, maxt=300011msec
Disk stats (read/write):
rbd0: ios=0/320813, merge=0/10001, ticks=0/5670847, in_queue=5677825, util=100.00%
And a job closer to what the actual workload would be (blocksize=200K, numjob=16, QD=32)
200k-16-32-randwrite-libaio: (groupid=0, jobs=16): err= 0: pid=4828: Wed Dec 2 18:58:53 2015
write: io=47305MB, bw=161367KB/s, iops=806, runt=300189msec
slat (usec): min=17, max=358430, avg=155.11, stdev=2361.49
clat (msec): min=9, max=3584, avg=613.88, stdev=168.68
lat (msec): min=10, max=3584, avg=614.04, stdev=168.66
clat percentiles (msec):
| 1.00th=[ 375], 5.00th=[ 469], 10.00th=[ 502], 20.00th=[ 537],
| 30.00th=[ 553], 40.00th=[ 578], 50.00th=[ 594], 60.00th=[ 603],
| 70.00th=[ 627], 80.00th=[ 652], 90.00th=[ 701], 95.00th=[ 881],
| 99.00th=[ 1205], 99.50th=[ 1483], 99.90th=[ 2638], 99.95th=[ 2671],
| 99.99th=[ 2999]
bw (KB /s): min= 260, max=18181, per=6.31%, avg=10189.40, stdev=2009.86
lat (msec) : 10=0.01%, 20=0.01%, 50=0.01%, 100=0.02%, 250=0.08%
lat (msec) : 500=9.26%, 750=83.21%, 1000=4.09%
cpu : usr=0.22%, sys=0.55%, ctx=719279, majf=0, minf=433
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=99.8%, >=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.1%, 64=0.0%, >=64=0.0%
issued : total=r=0/w=242203/d=0, short=r=0/w=0/d=0, drop=r=0/w=0/d=0
latency : target=0, window=0, percentile=100.00%, depth=32
Run status group 0 (all jobs):
WRITE: io=47305MB, aggrb=161367KB/s, minb=161367KB/s, maxb=161367KB/s, mint=300189msec, maxt=300189msec
Disk stats (read/write):
rbd0: ios=1/287809, merge=0/18393, ticks=50/5887593, in_queue=5887504, util=99.91%
The 4k block performance does not interest me so much but is given as a reference. I am more looking for throughput, but anyway, the numbers seem quite low.
Let's take IOPS, assuming the spinners can do 50 (4k) synced sustained IOPS (I hope they can do more ^^), we should be around 50x84/3 = 1400 IOPS, which is far from rados bench (538) and fio (847). And surprisingly fio numbers are greater than rados.
So I don't know wether I am missing something here or if something is going wrong (maybe both !).
Any input would be very valuable.
Thank you,
Adrien << File: ATT00001.txt >>
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-----------------------------------------------------------------------------------------
Adrien GILLARD
+33 (0)6 29 06 16 31
gillard.adrien@xxxxxxxxx
Adrien GILLARD
+33 (0)6 29 06 16 31
gillard.adrien@xxxxxxxxx
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