Hello, On 12/23/2015 04:38 PM, Lionel Bouton wrote: > Le 23/12/2015 16:18, Mart van Santen a écrit : >> Hi all, >> >> >> On 12/22/2015 01:55 PM, Wido den Hollander wrote: >>> On 22-12-15 13:43, Andrei Mikhailovsky wrote: >>>> Hello guys, >>>> >>>> Was wondering if anyone has done testing on Samsung PM863 120 GB version to see how it performs? IMHO the 480GB version seems like a waste for the journal as you only need to have a small disk size to fit 3-4 osd journals. Unless you get a far greater durability. >>>> >>> In that case I would look at the SM836 from Samsung. They are sold as >>> write-intensive SSDs. >>> >>> Wido >>> >> Today I received a small batch of SM863 (1.9TBs) disks. So maybe these >> testresults are helpfull for making a decision >> This is on an IBM X3550M4 with a MegaRaid SAS card (so not in jbod >> mode). Unfortunally I have no suitable JBOD card available at my test >> server so I'm stuck with the "RAID" layer in the HBA >> >> >> >> disabled drive cache, disabled controller cache >> --------------------------------------------------------------- >> >> >> 1 job >> ----------- >> Run status group 0 (all jobs): >> WRITE: io=906536KB, aggrb=15108KB/s, minb=15108KB/s, maxb=15108KB/s, >> mint=60001msec, maxt=60001msec >> >> Disk stats (read/write): >> sdd: ios=91/452978, merge=0/0, ticks=12/39032, in_queue=39016, util=65.04% > Either the MegaRaid SAS card is the bottleneck or SM863 1.9TB are 8x > slower than PM863 480GB on this particular test which is a bit > surprising: it would make the SM863 one of the slowest (or even the > slowest) DC SSD usable as Ceph journals. > Do you have any other SSD (if possible one of the models or one similar > to the ones listed on > http://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/ > which give more than 15MB/s with one job) connected to the same card > model you could test for comparison? The performance is strange. I've did some more tests, and it fluctuates a bit (which is strange, as the system is about idle), but I get between the 15MB to 30MB/s currently (1 job, 4k). But notably, I get about the same results (also same fluctuation) with a S3700 (100GB) I've plugged the SM863 in a different system, with an other SAS card, which gave a better result: (Symbios Logic SAS2308, but enclosure is a 3gpbs system) Run status group 0 (all jobs): WRITE: io=2713.7MB, aggrb=46311KB/s, minb=46311KB/s, maxb=46311KB/s, mint=60001msec, maxt=60001msec Disk stats (read/write): sdb: ios=9/694054, merge=0/0, ticks=0/49284, in_queue=49252, util=82.09% ~ 46 MB/s So, maybe you are right and is the HBA the bottleneck (LSI Logic / Symbios Logic MegaRAID SAS 2108). Under all cirumstances, I do not get close to the numbers of the PM863 quoted by Sebastien. But his site does not state what kind of HBA he is using.. Regards, Mart > > Lionel -- Mart van Santen Greenhost E: mart@xxxxxxxxxxxx T: +31 20 4890444 W: https://greenhost.nl A PGP signature can be attached to this e-mail, you need PGP software to verify it. My public key is available in keyserver(s) see: http://tinyurl.com/openpgp-manual PGP Fingerprint: CA85 EB11 2B70 042D AF66 B29A 6437 01A1 10A3 D3A5
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