Hi!
Of course, it isn't cheap at all, but we use Intel DC S3700 200Gb for ceph journals and DC S3700 400Gb in the SSD pool: same hosts, separate root in crushmap. SSD pool are not yet in production, journаlling SSDs works under production load for 10 months. They're in good condition - no faults, no degradation. We specially take 200Gb SSD for journals to reduce costs, and also have a higher than recommended OSD/SSD ratio: 1 SSD per 10-12 ODS, whille recommended 1/3 to 1/6. So, as a conclusion - I'll recommend you to get a bigger budget and buy durable and fast SSDs for Ceph. Megov Igor CIO, Yuterra ________________________________ От: ceph-users <ceph-users-boun...@lists.ceph.com> от имени Voloshanenko Igor <igor.voloshane...@gmail.com> Отправлено: 13 августа 2015 г. 15:54 Кому: Jan Schermer Копия: ceph-users@lists.ceph.com Тема: Re: [ceph-users] CEPH cache layer. Very slow So, good, but price for 845 DC PRO 400 GB higher in about 2x times than intel S3500 240G ((( Any other models? ((( 2015-08-13 15:45 GMT+03:00 Jan Schermer <j...@schermer.cz<mailto:j...@schermer.cz>>: I tested and can recommend the Samsung 845 DC PRO (make sure it is DC PRO and not just "PRO" or "DC EVO"!). Those were very cheap but are out of stock at the moment (here). Faster than Intels, cheaper, and slightly different technology (3D V-NAND) which IMO makes them superior without needing many tricks to do its job. Jan On 13 Aug 2015, at 14:40, Voloshanenko Igor <igor.voloshane...@gmail.com<mailto:igor.voloshane...@gmail.com>> wrote: Tnx, Irek! Will try! but another question to all, which SSD good enough for CEPH now? I'm looking into S3500 240G (I have some S3500 120G which show great results. Around 8x times better than Samsung) Possible you can give advice about other vendors/models with same or below price level as S3500 240G? 2015-08-13 12:11 GMT+03:00 Irek Fasikhov <malm...@gmail.com<mailto:malm...@gmail.com>>: Hi, Igor. Try to roll the patch here: http://www.theirek.com/blog/2014/02/16/patch-dlia-raboty-s-enierghoniezavisimym-keshiem-ssd-diskov P.S. I am no longer tracks changes in this direction(kernel), because we use already recommended SSD С уважением, Фасихов Ирек Нургаязович Моб.: +79229045757<tel:%2B79229045757> 2015-08-13 11:56 GMT+03:00 Voloshanenko Igor <igor.voloshane...@gmail.com<mailto:igor.voloshane...@gmail.com>>: So, after testing SSD (i wipe 1 SSD, and used it for tests) root@ix-s2:~# sudo fio --filename=/dev/sda --direct=1 --sync=1 --rw=write --bs=4k --numjobs=1 --iodepth=1 --runtime=60 --time_based --gr[53/1800] ting --name=journal-test journal-test: (g=0): rw=write, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=1 fio-2.1.3 Starting 1 process Jobs: 1 (f=1): [W] [100.0% done] [0KB/1152KB/0KB /s] [0/288/0 iops] [eta 00m:00s] journal-test: (groupid=0, jobs=1): err= 0: pid=2849460: Thu Aug 13 10:46:42 2015 write: io=68972KB, bw=1149.6KB/s, iops=287, runt= 60001msec clat (msec): min=2, max=15, avg= 3.48, stdev= 1.08 lat (msec): min=2, max=15, avg= 3.48, stdev= 1.08 clat percentiles (usec): | 1.00th=[ 2704], 5.00th=[ 2800], 10.00th=[ 2864], 20.00th=[ 2928], | 30.00th=[ 3024], 40.00th=[ 3088], 50.00th=[ 3280], 60.00th=[ 3408], | 70.00th=[ 3504], 80.00th=[ 3728], 90.00th=[ 3856], 95.00th=[ 4016], | 99.00th=[ 9024], 99.50th=[ 9280], 99.90th=[ 9792], 99.95th=[10048], | 99.99th=[14912] bw (KB /s): min= 1064, max= 1213, per=100.00%, avg=1150.07, stdev=34.31 lat (msec) : 4=94.99%, 10=4.96%, 20=0.05% cpu : usr=0.13%, sys=0.57%, ctx=17248, majf=0, minf=7 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=17243/d=0, short=r=0/w=0/d=0 Run status group 0 (all jobs): WRITE: io=68972KB, aggrb=1149KB/s, minb=1149KB/s, maxb=1149KB/s, mint=60001msec, maxt=60001msec Disk stats (read/write): sda: ios=0/17224, merge=0/0, ticks=0/59584, in_queue=59576, util=99.30% So, it's pain... SSD do only 287 iops on 4K... 1,1 MB/s I try to change cache mode : echo temporary write through > /sys/class/scsi_disk/2:0:0:0/cache_type echo temporary write through > /sys/class/scsi_disk/3:0:0:0/cache_type no luck, still same shit results, also i found this article: https://lkml.org/lkml/2013/11/20/264 pointed to old very simple patch, which disable CMD_FLUSH https://gist.github.com/TheCodeArtist/93dddcd6a21dc81414ba Has everybody better ideas, how to improve this? (or disable CMD_FLUSH without recompile kernel, i used ubuntu and 4.0.4 for now (4.x branch because SSD 850 Pro have issue with NCQ TRIM< and before 4.0.4 this exception was not included into libsata.c) 2015-08-12 19:17 GMT+03:00 Pieter Koorts <pieter.koo...@me.com<mailto:pieter.koo...@me.com>>: Hi Igor I suspect you have very much the same problem as me. https://www.mail-archive.com/ceph-users@lists.ceph.com/msg22260.html Basically Samsung drives (like many SATA SSD's) are very much hit and miss so you will need to test them like described here to see if they are any good. http://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/ To give you an idea my average performance went from 11MB/s (with Samsung SSD) to 30MB/s (without any SSD) on write performance. This is a very small cluster. Pieter On Aug 12, 2015, at 04:33 PM, Voloshanenko Igor <igor.voloshane...@gmail.com<mailto:igor.voloshane...@gmail.com>> wrote: Hi all, we have setup CEPH cluster with 60 OSD (2 diff types) (5 nodes, 12 disks on each, 10 HDD, 2 SSD) Also we cover this with custom crushmap with 2 root leaf ID WEIGHT TYPE NAME UP/DOWN REWEIGHT PRIMARY-AFFINITY -100 5.00000 root ssd -102 1.00000 host ix-s2-ssd 2 1.00000 osd.2 up 1.00000 1.00000 9 1.00000 osd.9 up 1.00000 1.00000 -103 1.00000 host ix-s3-ssd 3 1.00000 osd.3 up 1.00000 1.00000 7 1.00000 osd.7 up 1.00000 1.00000 -104 1.00000 host ix-s5-ssd 1 1.00000 osd.1 up 1.00000 1.00000 6 1.00000 osd.6 up 1.00000 1.00000 -105 1.00000 host ix-s6-ssd 4 1.00000 osd.4 up 1.00000 1.00000 8 1.00000 osd.8 up 1.00000 1.00000 -106 1.00000 host ix-s7-ssd 0 1.00000 osd.0 up 1.00000 1.00000 5 1.00000 osd.5 up 1.00000 1.00000 -1 5.00000 root platter -2 1.00000 host ix-s2-platter 13 1.00000 osd.13 up 1.00000 1.00000 17 1.00000 osd.17 up 1.00000 1.00000 21 1.00000 osd.21 up 1.00000 1.00000 27 1.00000 osd.27 up 1.00000 1.00000 32 1.00000 osd.32 up 1.00000 1.00000 37 1.00000 osd.37 up 1.00000 1.00000 44 1.00000 osd.44 up 1.00000 1.00000 48 1.00000 osd.48 up 1.00000 1.00000 55 1.00000 osd.55 up 1.00000 1.00000 59 1.00000 osd.59 up 1.00000 1.00000 -3 1.00000 host ix-s3-platter 14 1.00000 osd.14 up 1.00000 1.00000 18 1.00000 osd.18 up 1.00000 1.00000 23 1.00000 osd.23 up 1.00000 1.00000 28 1.00000 osd.28 up 1.00000 1.00000 33 1.00000 osd.33 up 1.00000 1.00000 39 1.00000 osd.39 up 1.00000 1.00000 43 1.00000 osd.43 up 1.00000 1.00000 47 1.00000 osd.47 up 1.00000 1.00000 54 1.00000 osd.54 up 1.00000 1.00000 58 1.00000 osd.58 up 1.00000 1.00000 -4 1.00000 host ix-s5-platter 11 1.00000 osd.11 up 1.00000 1.00000 16 1.00000 osd.16 up 1.00000 1.00000 22 1.00000 osd.22 up 1.00000 1.00000 26 1.00000 osd.26 up 1.00000 1.00000 31 1.00000 osd.31 up 1.00000 1.00000 36 1.00000 osd.36 up 1.00000 1.00000 41 1.00000 osd.41 up 1.00000 1.00000 46 1.00000 osd.46 up 1.00000 1.00000 51 1.00000 osd.51 up 1.00000 1.00000 56 1.00000 osd.56 up 1.00000 1.00000 -5 1.00000 host ix-s6-platter 12 1.00000 osd.12 up 1.00000 1.00000 19 1.00000 osd.19 up 1.00000 1.00000 24 1.00000 osd.24 up 1.00000 1.00000 29 1.00000 osd.29 up 1.00000 1.00000 34 1.00000 osd.34 up 1.00000 1.00000 38 1.00000 osd.38 up 1.00000 1.00000 42 1.00000 osd.42 up 1.00000 1.00000 50 1.00000 osd.50 up 1.00000 1.00000 53 1.00000 osd.53 up 1.00000 1.00000 57 1.00000 osd.57 up 1.00000 1.00000 -6 1.00000 host ix-s7-platter 10 1.00000 osd.10 up 1.00000 1.00000 15 1.00000 osd.15 up 1.00000 1.00000 20 1.00000 osd.20 up 1.00000 1.00000 25 1.00000 osd.25 up 1.00000 1.00000 30 1.00000 osd.30 up 1.00000 1.00000 35 1.00000 osd.35 up 1.00000 1.00000 40 1.00000 osd.40 up 1.00000 1.00000 45 1.00000 osd.45 up 1.00000 1.00000 49 1.00000 osd.49 up 1.00000 1.00000 52 1.00000 osd.52 up 1.00000 1.00000 Then create 2 pools, 1 on HDD (platters), 1 on SSD/ and put SSD pul in from of HDD pool (cache tier) now we receive very bad performance results from cluster. Even with rados bench we received very unstable performance with even zero speed. So it's create very big issues for our clients. I try to tune all possible values, including OSD, but still no luck. Also very unbelievble situation, when i do ceph tell... bench on SSD OSD - i receive about 20MB/s If for HDD - 67 MB/s... I don;t understand why cache pools which consist of SSD works so bad... We used Samsung 850 Pro 256 Gb as SSDs Can you guys give me advice please... Also very idiotic thing, when i set cache-mode to forward and try to flush-evict all object (not all object evicted, some busy (locked on KVM sides). but now i receive quite stable results for rados bench Total time run: 30.275871 Total writes made: 2076 Write size: 4194304 Bandwidth (MB/sec): 274.278 Stddev Bandwidth: 75.1445 Max bandwidth (MB/sec): 368 Min bandwidth (MB/sec): 0 Average Latency: 0.232892 Stddev Latency: 0.240356 Max latency: 2.01436 Min latency: 0.0716344 Without zeros, etc... So i don't understand how it's possible. Also interesting thing, when i disable overlay for pool, rados bench become around 70MB/s as for ordinary HDD, but in same time rados bench for SSD pool, which not used anymore show same bad results... So please, give me some direction to deeg... _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com<mailto:ceph-users@lists.ceph.com> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com<mailto:ceph-users@lists.ceph.com> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com<mailto:ceph-users@lists.ceph.com> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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