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Hi Mart,
El 23/11/15 a las 10:29, Mart van Santen escribió:
On 11/22/2015 10:01 PM, Robert LeBlanc wrote:
There have been numerous on the mailing
list of the Samsung EVO and
Pros failing far before their expected wear. This is most likely
due
to the 'uncommon' workload of Ceph and the controllers of those
drives
are not really designed to handle the continuous direct sync
writes
that Ceph does. Because of this they can fail without warning
(controller failure rather than MLC failure).
I'm new to the mailinglist and I'm scanning the archive
currently. And I'm getting a sense of the Samsung Evo quality
disks. If i understand correctly, is is at least advise to put DC
grade Journals in front om them to safe them a bit from failure.
For example intel 750's.
I don't think Intel 750's are DC grade. I don't have any of them
though.
However, is there experience in when the Evo's fail in the Ceph
scenarion? For example, is wear leveling is according SMART about
40%, it's time to replace your disks? Or is it just random.
Actually we are using mostly Crucial drives (m550, mx200's), there
is not a lot about them on the list. Do other people use them and
what's there experience so far. I expect about the same quality of
the Samsung Evo's, but I'm not sure if that is the correct
conclusion.
My experience with Samsung 840 pro is that they can't be used for
Ceph at all. In case of Crucial M550, they are slow and have little
endurance for ceph use, but I have used them and seemed reliable
during warranty lifetime (we retired them for performance reasons).
About SSD failure in general, do they normally fail hard, or are
they just getting unbearable slow? We do measure/graph disks
'busy' performance, and use that as an indicator if a disk is
getting slow. Is this is a sensible approach?
Just don't do it. Use DC SSDs, like intel S3xxx, or Samsung DC Pro,
or something like that. You will save a lot of time and effort, and
possibly also money.
Cheers
Eneko
--
Zuzendari Teknikoa / Director Técnico
Binovo IT Human Project, S.L.
Telf. 943575997
943493611
Astigarraga bidea 2, planta 6 dcha., ofi. 3-2; 20180 Oiartzun (Gipuzkoa)
www.binovo.es
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