Hello, On Wed, 8 Jul 2015 00:33:59 +1200 Andrew Thrift wrote: > We are running NVMe Intel P3700's as journals for about 8 months now. > 1x P3700 per 6x OSD. > > So far they have been reliable. > > We are using S3700, S3710 and P3700 as journals and there is _currently_ > no real benefit of the P3700 over the SATA units as journals for Ceph. > Thanks for confirming that, this is exactly what I expected/suspected. Christian > > Regards, > > > > Andrew > > On Tue, Jul 7, 2015 at 10:12 PM, Christian Balzer <chibi@xxxxxxx> wrote: > > > > > Hello, > > > > On Tue, 7 Jul 2015 09:51:56 +0000 Van Leeuwen, Robert wrote: > > > > > > I'm wondering if anyone is using NVME SSDs for journals? > > > > Intel 750 series 400GB NVME SSD offers good performance and price > > > > in comparison to let say Intel S3700 400GB. > > > > http://ark.intel.com/compare/71915,86740 My concern would be MTBF / > > > > TBW which is only 1.2M hours and 70GB per day for 5yrs or 127 TBW. > > > > Intel 750 1.2TB has a slightly better 219 TBW but still it can be a > > > > bit too low for some people. Thoughts? > > > > > This has of course been already discussed here, when those SSDs were > > initially released. > > > > Basically what Robert wrote already. > > > > The 750s are blazingly fast, much faster in fact that I see current > > versions of Ceph taking full advantage of. > > One would be tempted to put a lot of journals on them and thus wear > > them out quickly. > > > > Calculate the TBW/$ of them versus high endurance 3700s or even 3610s > > in the middle of the field. > > Unless you know PRECISELY what your workload is going to be, go with > > the next more durable model. ^o^ > > > > Christian > > > > > Do not think this would be a good choice: > > > These have about 0.2 Drive Writes Per Day. > > > At my previous employer we used one 300GB Intel S3500 (0.3 DWPD) as a > > > journal per 5 X 1TB 7200RPM disk. The cluster was not heavily used > > > and burned through that SSD in a year. > > > > > > As you mentioned getting bigger SSDs will help a bit since you have > > > more NAND chips to spread the load around. It is still more cost > > > efficient to go for a smaller S3700 series though. E.g. The Intel > > > 750, 1.2TB costs more then a 400GB S3700 and has a lot less > > > endurance (about 200GB per day vs 4TB per day) > > > > > > Cheers, > > > Robert van Leeuwen > > > > > > -- > > Christian Balzer Network/Systems Engineer > > chibi@xxxxxxx Global OnLine Japan/Fusion Communications > > http://www.gol.com/ > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Fusion Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 |