Hi, >>What I'm trying to get from the list is /why/ the "enterprise" drives >>are important. Performance? Reliability? Something else? performance, for sure (for SYNC write, https://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/) Reliabity : yes, enteprise drive have supercapacitor in case of powerfailure, and endurance (1 DWPD for 3520, 3 DWPD for 3610) >>Also, 4 x Intel DC S3520 costs as much as 1 x Intel DC S3610. Obviously >>the single drive leaves more bays free for OSD disks, but is there any >>other reason a single S3610 is preferable to 4 S3520s? Wouldn't 4xS3520s >>mean: where do you see this price difference ? for me , S3520 are around 25-30% cheaper than S3610 ----- Mail original ----- De: "Adam Carheden" <carheden@xxxxxxxx> À: "ceph-users" <ceph-users@xxxxxxxxxxxxxx> Envoyé: Mercredi 26 Avril 2017 16:53:48 Objet: Re: Sharing SSD journals and SSD drive choice What I'm trying to get from the list is /why/ the "enterprise" drives are important. Performance? Reliability? Something else? The Intel was the only one I was seriously considering. The others were just ones I had for other purposes, so I thought I'd see how they fared in benchmarks. The Intel was the clear winner, but my tests did show that throughput tanked with more threads. Hypothetically, if I was throwing 16 OSDs at it, all with osd op threads = 2, do the benchmarks below not show that the Hynix would be a better choice (at least for performance)? Also, 4 x Intel DC S3520 costs as much as 1 x Intel DC S3610. Obviously the single drive leaves more bays free for OSD disks, but is there any other reason a single S3610 is preferable to 4 S3520s? Wouldn't 4xS3520s mean: a) fewer OSDs go down if the SSD fails b) better throughput (I'm speculating that the S3610 isn't 4 times faster than the S3520) c) load spread across 4 SATA channels (I suppose this doesn't really matter since the drives can't throttle the SATA bus). -- Adam Carheden On 04/26/2017 01:55 AM, Eneko Lacunza wrote: > Adam, > > What David said before about SSD drives is very important. I will tell > you another way: use enterprise grade SSD drives, not consumer grade. > Also, pay attention to endurance. > > The only suitable drive for Ceph I see in your tests is SSDSC2BB150G7, > and probably it isn't even the most suitable SATA SSD disk from Intel; > better use S3610 o S3710 series. > > Cheers > Eneko > > El 25/04/17 a las 21:02, Adam Carheden escribió: >> On 04/25/2017 11:57 AM, David wrote: >>> On 19 Apr 2017 18:01, "Adam Carheden" <carheden@xxxxxxxx >>> <mailto:carheden@xxxxxxxx>> wrote: >>> >>> Does anyone know if XFS uses a single thread to write to it's >>> journal? >>> >>> >>> You probably know this but just to avoid any confusion, the journal in >>> this context isn't the metadata journaling in XFS, it's a separate >>> journal written to by the OSD daemons >> Ha! I didn't know that. >> >>> I think the number of threads per OSD is controlled by the 'osd op >>> threads' setting which defaults to 2 >> So the ideal (for performance) CEPH cluster would be one SSD per HDD >> with 'osd op threads' set to whatever value fio shows as the optimal >> number of threads for that drive then? >> >>> I would avoid the SanDisk and Hynix. The s3500 isn't too bad. Perhaps >>> consider going up to a 37xx and putting more OSDs on it. Of course with >>> the caveat that you'll lose more OSDs if it goes down. >> Why would you avoid the SanDisk and Hynix? Reliability (I think those >> two are both TLC)? Brand trust? If it's my benchmarks in my previous >> email, why not the Hynix? It's slower than the Intel, but sort of >> decent, at lease compared to the SanDisk. >> >> My final numbers are below, including an older Samsung Evo (MCL I think) >> which did horribly, though not as bad as the SanDisk. The Seagate is a >> 10kRPM SAS "spinny" drive I tested as a control/SSD-to-HDD comparison. >> >> SanDisk SDSSDA240G, fio 1 jobs: 7.0 MB/s (5 trials) >> >> >> SanDisk SDSSDA240G, fio 2 jobs: 7.6 MB/s (5 trials) >> >> >> SanDisk SDSSDA240G, fio 4 jobs: 7.5 MB/s (5 trials) >> >> >> SanDisk SDSSDA240G, fio 8 jobs: 7.6 MB/s (5 trials) >> >> >> SanDisk SDSSDA240G, fio 16 jobs: 7.6 MB/s (5 trials) >> >> >> SanDisk SDSSDA240G, fio 32 jobs: 7.6 MB/s (5 trials) >> >> >> SanDisk SDSSDA240G, fio 64 jobs: 7.6 MB/s (5 trials) >> >> >> HFS250G32TND-N1A2A 30000P10, fio 1 jobs: 4.2 MB/s (5 trials) >> >> >> HFS250G32TND-N1A2A 30000P10, fio 2 jobs: 0.6 MB/s (5 trials) >> >> >> HFS250G32TND-N1A2A 30000P10, fio 4 jobs: 7.5 MB/s (5 trials) >> >> >> HFS250G32TND-N1A2A 30000P10, fio 8 jobs: 17.6 MB/s (5 trials) >> >> >> HFS250G32TND-N1A2A 30000P10, fio 16 jobs: 32.4 MB/s (5 trials) >> >> >> HFS250G32TND-N1A2A 30000P10, fio 32 jobs: 64.4 MB/s (5 trials) >> >> >> HFS250G32TND-N1A2A 30000P10, fio 64 jobs: 71.6 MB/s (5 trials) >> >> >> SAMSUNG SSD, fio 1 jobs: 2.2 MB/s (5 trials) >> >> >> SAMSUNG SSD, fio 2 jobs: 3.9 MB/s (5 trials) >> >> >> SAMSUNG SSD, fio 4 jobs: 7.1 MB/s (5 trials) >> >> >> SAMSUNG SSD, fio 8 jobs: 12.0 MB/s (5 trials) >> >> >> SAMSUNG SSD, fio 16 jobs: 18.3 MB/s (5 trials) >> >> >> SAMSUNG SSD, fio 32 jobs: 25.4 MB/s (5 trials) >> >> >> SAMSUNG SSD, fio 64 jobs: 26.5 MB/s (5 trials) >> >> >> INTEL SSDSC2BB150G7, fio 1 jobs: 91.2 MB/s (5 trials) >> >> >> INTEL SSDSC2BB150G7, fio 2 jobs: 132.4 MB/s (5 trials) >> >> >> INTEL SSDSC2BB150G7, fio 4 jobs: 138.2 MB/s (5 trials) >> >> >> INTEL SSDSC2BB150G7, fio 8 jobs: 116.9 MB/s (5 trials) >> >> >> INTEL SSDSC2BB150G7, fio 16 jobs: 61.8 MB/s (5 trials) >> INTEL SSDSC2BB150G7, fio 32 jobs: 22.7 MB/s (5 trials) >> INTEL SSDSC2BB150G7, fio 64 jobs: 16.9 MB/s (5 trials) >> SEAGATE ST9300603SS, fio 1 jobs: 0.7 MB/s (5 trials) >> SEAGATE ST9300603SS, fio 2 jobs: 0.9 MB/s (5 trials) >> SEAGATE ST9300603SS, fio 4 jobs: 1.6 MB/s (5 trials) >> SEAGATE ST9300603SS, fio 8 jobs: 2.0 MB/s (5 trials) >> SEAGATE ST9300603SS, fio 16 jobs: 4.6 MB/s (5 trials) >> SEAGATE ST9300603SS, fio 32 jobs: 6.9 MB/s (5 trials) >> SEAGATE ST9300603SS, fio 64 jobs: 0.6 MB/s (5 trials) >> >> For those who come across this and are looking for drives for purposes >> other than CEPH, those are all sequential write numbers with caching >> disabled, a very CEPH-journal-specific test. The SanDisk held it's own >> against the Intel using some benchmarks on Windows that didn't disable >> caching. It may very well be a perfectly good drive for other purposes. >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@xxxxxxxxxxxxxx >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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