Hi,

We settled on Samsung pro 840 240GB drives 1½ year ago and we've been happy
so far. We've over-provisioned them a lot (left 120GB unpartitioned).

We have 16x 240GB and 32x 500GB - we've lost 1x 500GB so far.

smartctl states something like
Wear = 092%, Hours = 12883, Datawritten = 15321.83 TB avg on those. I think
that is ~30TB/day if I'm doing the calc right.

Not to advertise or say every samsung 840 ssd is like this:
http://www.vojcik.net/samsung-ssd-840-endurance-destruct-test/

Cheers,
Martin


On Wed, Oct 1, 2014 at 10:18 AM, Christian Balzer <ch...@gol.com> wrote:

> 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
> > > >> _______________________________________________
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> > > >> ceph-users@lists.ceph.com
> > > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> > > >
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> > >
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>
>
> --
> Christian Balzer        Network/Systems Engineer
> ch...@gol.com           Global OnLine Japan/Fusion Communications
> http://www.gol.com/
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