On Wed, 1 Oct 2014 09:28:12 +0200 Kasper Dieter wrote: > On Tue, Sep 30, 2014 at 04:38:41PM +0200, Mark Nelson wrote: > > On 09/29/2014 03:58 AM, Dan Van Der Ster wrote: > > > Hi Emmanuel, > > > This is interesting, because we?ve had sales guys telling us that > > > those Samsung drives are definitely the best for a Ceph journal O_o ! > > > > Our sales guys or Samsung sales guys? :) If it was ours, let me know. > > > > > The conventional wisdom has been to use the Intel DC S3700 because > > > of its massive durability. > > > > The S3700 is definitely one of the better drives on the market for > > Ceph journals. Some of the higher end PCIE SSDs have pretty high > > durability (and performance) as well, but cost more (though you can > > save SAS bay space, so it's a trade-off). > Intel P3700 could be an alternative with 10 Drive-Writes/Day for 5 years > (see attachment) > They're certainly nice and competitively priced (TBW/$ wise at least). However as I said in another thread, once your SSDs start to outlive your planned server deployment time (in our case 5 years) that's probably good enough.
It's all about finding the balance between cost, speed (BW and IOPS), durability and space. For example I'm currently building a cluster based on 2U, 12 hotswap bays servers (because I already had 2 floating around) and am using 4 100GB DC S3700 (at US$200 each) and 8 HDDS in them. Putting in a 400GB DC P3700 (US$1200( instead and 4 more HDDs would have pushed me over the budget and left me with a less than 30% "used" SSD 5 years later, at a time when we clearly can expect these things to be massively faster and cheaper. Now if you're actually having a cluster that would wear out a P3700 in 5 years (or you're planning to run your machines until they burst into flames), then that's another story. ^.^ Christian > -Dieter > > > > > > > > > Anyway, I?m curious what do the SMART counters say on your SSDs?? > > > are they really failing due to worn out P/E cycles or is it > > > something else? > > > > > > Cheers, Dan > > > > > > > > >> On 29 Sep 2014, at 10:31, Emmanuel Lacour <elac...@easter-eggs.com> > > >> wrote: > > >> > > >> > > >> Dear ceph users, > > >> > > >> > > >> we are managing ceph clusters since 1 year now. Our setup is > > >> typically made of Supermicro servers with OSD sata drives and > > >> journal on SSD. > > >> > > >> Those SSD are all failing one after the other after one year :( > > >> > > >> We used Samsung 850 pro (120Go) with two setup (small nodes with 2 > > >> ssd, 2 HD in 1U): > > >> > > >> 1) raid 1 :( (bad idea, each SSD support all the OSDs journals > > >> writes :() 2) raid 1 for OS (nearly no writes) and dedicated > > >> partition for journals (one per OSD) > > >> > > >> > > >> I'm convinced that the second setup is better and we migrate old > > >> setup to this one. > > >> > > >> Thought, statistics gives 60GB (option 2) to 100 GB (option 1) > > >> writes per day on SSD on a not really over loaded cluster. Samsung > > >> claims to give 5 years warranty if under 40GB/day. Those numbers > > >> seems very low to me. > > >> > > >> What are your experiences on this? What write volumes do you > > >> encounter, on wich SSD models, which setup and what MTBF? > > >> > > >> > > >> -- > > >> Easter-eggs Spécialiste GNU/Linux > > >> 44-46 rue de l'Ouest - 75014 Paris - France - Métro Gaité > > >> Phone: +33 (0) 1 43 35 00 37 - Fax: +33 (0) 1 43 35 00 76 > > >> mailto:elac...@easter-eggs.com - http://www.easter-eggs.com > > >> _______________________________________________ > > >> ceph-users mailing list > > >> ceph-users@lists.ceph.com > > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > _______________________________________________ > > > ceph-users mailing list > > > ceph-users@lists.ceph.com > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- Christian Balzer Network/Systems Engineer ch...@gol.com Global OnLine Japan/Fusion Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
