Perfect. There's the answer, thanks. DWPD seem like an idiotic and meaningless measurement, but the endurance figures on those data sheets give the total TB or PB written, which is what I really want to see. DC S3510: 0.56 TBW/GB of drive capacity DC S3610: 6.60 TBW/GB of drive capacity DC S3710: 20.00 TBW/GB of drive capacity Strangely enough there seems to be quite a bit more variance by drive size (larger drives being better) in the better drives. Possibly that's just due to rounding of the number presented on the data sheet though. Thanks -- Adam Carheden Systems Administrator - NCAR/RAL x2753 On 05/01/2017 02:59 AM, Jens Dueholm Christensen wrote: > Sorry for topposting, but.. > > The Intel 35xx drives are rated for a much lower DWPD (drive-writes-per-day) than the 36xx or 37xx models. > > Keep in mind that a single SSD that acts as journal for 5 OSDs will recieve ALL writes for those 5 OSDs before the data is moved off to the OSDs actual data drives. > > This makes for quite a lot of writes, and along with the consumer/enterprise advice others have written about, your SSD journal devices will recieve quite a lot of writes over time. > > The S3510 is rated for 0.3 DWPD for 5 years (http://www.intel.com/content/www/us/en/solid-state-drives/ssd-dc-s3510-spec.html) > The S3610 is rated for 3 DWPD for 5 years (http://www.intel.com/content/www/us/en/solid-state-drives/ssd-dc-s3610-spec.html) > The S3710 is rated for 10 DWPD for 5 years (http://www.intel.com/content/www/us/en/solid-state-drives/ssd-dc-s3710-spec.html) > > A 480GB S3510 has no endurance left once you have written 0.275PB to it. > A 480GB S3610 has no endurance left once you have written 3.7PB to it. > A 400GB S3710 has no endurance left once you have written 8.3PB to it. > > This makes for quite a lot of difference over time - even if a S3510 wil only act as journal for 1 or 2 OSDs, it will wear out much much much faster than others. > > And I know I've used the xx10 models above, but the xx00 models have all been replaced by those newer models now. > > And yes, the xx10 models are using MLC NAND, but so were the xx00 models, that have a proven trackrecord and delivers what Intel promised in the datasheet. > > You could try and take a look at some of the enterprise SSDs that Samsung has launched. > Price-wise they are very competitive to Intel, but I want to see (or at least hear from others) if they can deliver what their datasheet promises. > Samsungs consumer SSDs did not (840/850 Pro), so I'm only using S3710s in my cluster. > > > Before I created our own cluster some time ago, I found these threads from the mailinglist regarding the exact same disks we had been expecting to use (Samsung 840/850 Pro), that was quickly changed to Intel S3710s: > > http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-November/044258.html > https://www.mail-archive.com/ceph-users@xxxxxxxxxxxxxx/msg17369.html > > A longish thread about Samsung consumer drives: > http://lists.ceph.com/pipermail/ceph-users-ceph.com/2015-April/000572.html > - highlights from that thread: > - http://lists.ceph.com/pipermail/ceph-users-ceph.com/2015-April/000610.html > - http://lists.ceph.com/pipermail/ceph-users-ceph.com/2015-April/000611.html > - http://lists.ceph.com/pipermail/ceph-users-ceph.com/2015-April/000798.html > > Regards, > Jens Dueholm Christensen > Rambøll Survey IT > > -----Original Message----- > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Adam Carheden > Sent: Wednesday, April 26, 2017 5:54 PM > To: ceph-users@xxxxxxxxxxxxxx > Subject: Re: Sharing SSD journals and SSD drive choice > > Thanks everyone for the replies. > > I will be avoiding TLC drives, it was just something easy to benchmark > with existing equipment. I hadn't though of unscrupulous data durability > lies or performance suddenly tanking in unpredictable ways. I guess it > all comes down to trusting the vendor since it would be expensive in > time and $$ to test for such things. > > Any thoughts on multiple Intel 35XX vs a single 36XX/37XX? All have "DC" > prefixes and are listed in the Data Center section of their marketing > pages, so I assume they'll all have the same quality underlying NAND. > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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