Sebastien, No timeline yet.. Couple of issues here. 1. I don't think FileStore is a solution for SSDs because of its double write. WA will be >=2 always. So far can't find a way to replace Ceph journal for filesystem backend. 2. The existing key-value backend like leveldb/Rocksdb also are not flash optimized. Yes, Ceph journal will not be needed anymore but I guess compaction overhead for Flash will be too much. Thanks & Regards Somnath -----Original Message----- From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Sebastien Han Sent: Friday, August 29, 2014 3:17 AM To: ceph-users Subject: Re: [Single OSD performance on SSD] Can't go over 3, 2K IOPS Thanks a lot for the answers, even if we drifted from the main subject a little bit. Thanks Somnath for sharing this, when can we expect any codes that might improve _write_ performance? @Mark thanks trying this :) Unfortunately using nobarrier and another dedicated SSD for the journal (plus your ceph setting) didn't bring much, now I can reach 3,5K IOPS. By any chance, would it be possible for you to test with a single OSD SSD? On 28 Aug 2014, at 18:11, Sebastien Han <sebastien.han at enovance.com> wrote: > Hey all, > > It has been a while since the last thread performance related on the > ML :p I've been running some experiment to see how much I can get from an SSD on a Ceph cluster. > To achieve that I did something pretty simple: > > * Debian wheezy 7.6 > * kernel from debian 3.14-0.bpo.2-amd64 > * 1 cluster, 3 mons (i'd like to keep this realistic since in a real > deployment i'll use 3) > * 1 OSD backed by an SSD (journal and osd data on the same device) > * 1 replica count of 1 > * partitions are perfectly aligned > * io scheduler is set to noon but deadline was showing the same > results > * no updatedb running > > About the box: > > * 32GB of RAM > * 12 cores with HT @ 2,4 GHz > * WB cache is enabled on the controller > * 10Gbps network (doesn't help here) > > The SSD is a 200G Intel DC S3700 and is capable of delivering around > 29K iops with random 4k writes (my fio results) As a benchmark tool I used fio with the rbd engine (thanks deutsche telekom guys!). > > O_DIECT and D_SYNC don't seem to be a problem for the SSD: > > # dd if=/dev/urandom of=rand.file bs=4k count=65536 > 65536+0 records in > 65536+0 records out > 268435456 bytes (268 MB) copied, 29.5477 s, 9.1 MB/s > > # du -sh rand.file > 256M rand.file > > # dd if=rand.file of=/dev/sdo bs=4k count=65536 oflag=dsync,direct > 65536+0 records in > 65536+0 records out > 268435456 bytes (268 MB) copied, 2.73628 s, 98.1 MB/s > > See my ceph.conf: > > [global] > auth cluster required = cephx > auth service required = cephx > auth client required = cephx > fsid = 857b8609-8c9b-499e-9161-2ea67ba51c97 > osd pool default pg num = 4096 > osd pool default pgp num = 4096 > osd pool default size = 2 > osd crush chooseleaf type = 0 > > debug lockdep = 0/0 > debug context = 0/0 > debug crush = 0/0 > debug buffer = 0/0 > debug timer = 0/0 > debug journaler = 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 > > [mon] > mon osd down out interval = 600 > mon osd min down reporters = 13 > [mon.ceph-01] > host = ceph-01 > mon addr = 172.20.20.171 > [mon.ceph-02] > host = ceph-02 > mon addr = 172.20.20.172 > [mon.ceph-03] > host = ceph-03 > mon addr = 172.20.20.173 > > debug lockdep = 0/0 > debug context = 0/0 > debug crush = 0/0 > debug buffer = 0/0 > debug timer = 0/0 > debug journaler = 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 > > [osd] > osd mkfs type = xfs > osd mkfs options xfs = -f -i size=2048 osd mount options xfs = > rw,noatime,logbsize=256k,delaylog osd journal size = 20480 > cluster_network = 172.20.20.0/24 public_network = 172.20.20.0/24 osd > mon heartbeat interval = 30 # Performance tuning filestore merge > threshold = 40 filestore split multiple = 8 osd op threads = 8 # > Recovery tuning osd recovery max active = 1 osd max backfills = 1 > osd recovery op priority = 1 > > > debug lockdep = 0/0 > debug context = 0/0 > debug crush = 0/0 > debug buffer = 0/0 > debug timer = 0/0 > debug journaler = 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 > > Disabling all debugging made me win 200/300 more IOPS. > > See my fio template: > > [global] > #logging > #write_iops_log=write_iops_log > #write_bw_log=write_bw_log > #write_lat_log=write_lat_lo > > time_based > runtime=60 > > ioengine=rbd > clientname=admin > pool=test > rbdname=fio > invalidate=0 # mandatory > #rw=randwrite > rw=write > bs=4k > #bs=32m > size=5G > group_reporting > > [rbd_iodepth32] > iodepth=32 > direct=1 > > See my rio output: > > rbd_iodepth32: (g=0): rw=write, bs=4K-4K/4K-4K/4K-4K, ioengine=rbd, > iodepth=32 fio-2.1.11-14-gb74e Starting 1 process rbd engine: RBD > version: 0.1.8 > Jobs: 1 (f=1): [W(1)] [100.0% done] [0KB/12876KB/0KB /s] [0/3219/0 > iops] [eta 00m:00s] > rbd_iodepth32: (groupid=0, jobs=1): err= 0: pid=32116: Thu Aug 28 > 00:28:26 2014 > write: io=771448KB, bw=12855KB/s, iops=3213, runt= 60010msec > slat (usec): min=42, max=1578, avg=66.50, stdev=16.96 > clat (msec): min=1, max=28, avg= 9.85, stdev= 1.48 > lat (msec): min=1, max=28, avg= 9.92, stdev= 1.47 > clat percentiles (usec): > | 1.00th=[ 6368], 5.00th=[ 8256], 10.00th=[ 8640], 20.00th=[ 9152], > | 30.00th=[ 9408], 40.00th=[ 9664], 50.00th=[ 9792], 60.00th=[10048], > | 70.00th=[10176], 80.00th=[10560], 90.00th=[10944], 95.00th=[11456], > | 99.00th=[13120], 99.50th=[16768], 99.90th=[25984], 99.95th=[27008], > | 99.99th=[28032] > bw (KB /s): min=11864, max=13808, per=100.00%, avg=12864.36, stdev=407.35 > lat (msec) : 2=0.03%, 4=0.54%, 10=59.79%, 20=39.24%, 50=0.41% > cpu : usr=19.15%, sys=4.69%, ctx=326309, majf=0, minf=426088 > IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=33.9%, 32=66.1%, >=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=99.6%, 8=0.4%, 16=0.1%, 32=0.1%, 64=0.0%, >=64=0.0% > issued : total=r=0/w=192862/d=0, short=r=0/w=0/d=0 > latency : target=0, window=0, percentile=100.00%, depth=32 > > Run status group 0 (all jobs): > WRITE: io=771448KB, aggrb=12855KB/s, minb=12855KB/s, maxb=12855KB/s, > mint=60010msec, maxt=60010msec > > Disk stats (read/write): > dm-1: ios=0/49, merge=0/0, ticks=0/12, in_queue=12, util=0.01%, > aggrios=0/22, aggrmerge=0/27, aggrticks=0/12, aggrin_queue=12, > aggrutil=0.01% > sda: ios=0/22, merge=0/27, ticks=0/12, in_queue=12, util=0.01% > > I tried to tweak several parameters like: > > filestore_wbthrottle_xfs_ios_start_flusher = 10000 > filestore_wbthrottle_xfs_ios_hard_limit = 10000 > filestore_wbthrottle_btrfs_ios_start_flusher = 10000 > filestore_wbthrottle_btrfs_ios_hard_limit = 10000 filestore queue max > ops = 2000 > > But didn't any improvement. > > Then I tried other things: > > * Increasing the io_depth up to 256 or 512 gave me between 50 to 100 more IOPS but it's not a realistic workload anymore and not that significant. > * adding another SSD for the journal, still getting 3,2K IOPS > * I tried with rbd bench and I also got 3K IOPS > * I ran the test on a client machine and then locally on the server, > still getting 3,2K IOPS > * put the journal in memory, still getting 3,2K IOPS > * with 2 clients running the test in parallel I got a total of 3,6K > IOPS but I don't seem to be able to go over > * I tried is to add another OSD to that SSD, so I had 2 OSD and 2 journals on 1 SSD, got 4,5K IOPS YAY! > > Given the results of the last time it seems that something is limiting the number of IOPS per OSD process. > > Running the test on a client or locally didn't show any difference. > So it looks to me that there is some contention within Ceph that might cause this. > > I also ran perf and looked at the output, everything looks decent, but someone might want to have a look at it :). > > We have been able to reproduce this on 3 distinct platforms with some deviations (because of the hardware) but the behaviour is the same. > Any thoughts will be highly appreciated, only getting 3,2k out of an 29K IOPS SSD is a bit frustrating :). > > Cheers. > ---- > S?bastien Han > Cloud Architect > > "Always give 100%. Unless you're giving blood." > > Phone: +33 (0)1 49 70 99 72 > Mail: sebastien.han at enovance.com > Address : 11 bis, rue Roqu?pine - 75008 Paris Web : www.enovance.com - > Twitter : @enovance > > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com Cheers. ---- S?bastien Han Cloud Architect "Always give 100%. Unless you're giving blood." Phone: +33 (0)1 49 70 99 72 Mail: sebastien.han at enovance.com Address : 11 bis, rue Roqu?pine - 75008 Paris Web : www.enovance.com - Twitter : @enovance ________________________________ PLEASE NOTE: The information contained in this electronic mail message is intended only for the use of the designated recipient(s) named above. 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