Hi Mart,
I agree with Eneko, I had 72 of the Samaung Evo drives in service for journals (4:1) and ended up replacing them all within 9 months with Intel DC 3700's due to high number of failures and very poor performance resulting in frequent blocked ops.
Just stick with the Intel Data Center Grade drives and you should be fine.
Thanks
On Mon, Nov 23, 2015 at 9:42 AM, Eneko Lacunza <elacunza@xxxxxxxxx> wrote:
Hi Mart,
El 23/11/15 a las 10:29, Mart van Santen escribió:
I don't think Intel 750's are DC grade. I don't have any of them though.
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.
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).
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.
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
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