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.
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/
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