There is http://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/
On the other hand, I'm not sure if SSD vendors would be happy to see their device listed performing total crap (for Journaling) ...but yes, I vote for having some oficial page if possible !
On 7 September 2015 at 11:12, Eino Tuominen <eino@xxxxxx> wrote:
Hello,
Should we (somebody, please?) gather up a comprehensive list of suitable SSD devices to use as ceph journals? This seems to be a FAQ, and it would be nice if all the knowledge and user experiences from several different threads could be referenced easily in the future. I took a look at wiki.ceph.org and there was nothing on this.
--
Eino Tuominen
-----Original Message-----
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Jan Schermer
Sent: 7. syyskuuta 2015 11:44
To: Christian Balzer
Cc: ceph-users; Межов Игорь Александрович
Subject: Re: which SSD / experiences with Samsung 843T vs. Intel s3700
Re: Samsungs - I feel some of you are mixing and confusing different Samsung drives.
There is a DC line of Samsung drives meant for DataCenter use. Those have EVO (write once read many) and PRO (write mostly) variants.
You don't want to go anywhere near the EVO line with Ceph.
Then there are "regular" EVO and PRO drives - they are not meant for server use so don't use them.
The main difference is that the "DC" line should provide reliable and stable performance over time, no surprises, while the desktop drives can just pause and perform garbage collection and have completely different cache setup. If you torture desktop drive hard enough it will protect itself (slow down to a crawl).
So the only usable drivess for us are "DC PRO" and nothing else.
Jan
> On 05 Sep 2015, at 04:36, Christian Balzer <chibi@xxxxxxx> wrote:
>
>
> Hello,
>
> On Fri, 4 Sep 2015 22:37:06 +0000 Межов Игорь Александрович wrote:
>
>> Hi!
>>
>>
>> Have worked with Intel DC S3700 200Gb. Due to budget restrictions, one
>>
>> ssd hosts a system volume and 1:12 OSD journals. 6 nodes, 120Tb raw
>> space.
>>
> Meaning you're limited to 360MB/s writes per node at best.
> But yes, I do understand budget constraints. ^o^
>
>> Cluster serves as RBD storage for ~100VM.
>>
>>
>> Not a single failure per year - all devices are healthy.
>>
>> The remainig resource (by smart) is ~92%.
>>
> I use 1:2 or 1:3 journals and haven't made any dent into my 200GB S3700
> yet.
>
>>
>> Now we're try to use DC S3710 for journals.
>
> As I wrote a few days ago, unless you go for the 400GB version the the
> 200GB S3710 is actually slower (for journal purposes) than the 3700, as
> sequential write speed is the key factor here.
>
> Christian
> --
> Christian Balzer Network/Systems Engineer
> chibi@xxxxxxx Global OnLine Japan/Fusion Communications
> http://www.gol.com/
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