From: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
To: Mark Nelson <mark.nelson@inktank.com>
Cc: Alexandre DERUMIER <aderumier@odiso.com>, ceph-devel@vger.kernel.org
Subject: Re: Heavy speed difference between rbd and custom pool
Date: Tue, 19 Jun 2012 15:14:18 +0200 [thread overview]
Message-ID: <4FE07B2A.7080209@profihost.ag> (raw)
In-Reply-To: <4FE0782A.1060104@inktank.com>
Am 19.06.2012 15:01, schrieb Mark Nelson:
> On 06/19/2012 01:32 AM, Stefan Priebe - Profihost AG wrote:
>> Am 19.06.2012 06:41, schrieb Alexandre DERUMIER:
>>> Hi Stephann
>>> recommandations are 30-50 PGS by osd if I remember.
>>>
>> rbd, data and metadata have 2176 PGs with 12 OSD. This is 181,333333333
>> per OSD?!
>>
>> Stefan
>
> That's probably fine, it just means that you will have a better
> pseudo-random distribution of OSD combinations (It does have higher
> cpu/memory overhead though). Figuring out how many PGs you should have
> per OSD depends on a lot of factors including how many OSDs you have,
> how many nodes, CPU, memory, etc. I'm guessing ~180 per OSD won't cause
> problems. On the other hand, with low OSD counts you could probably have
> fewer and be fine too.
But this number 2176 of PGs were set while doing mkcephfs - how is it
calculated?
Stefan
next prev parent reply other threads:[~2012-06-19 13:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-18 21:39 Heavy speed difference between rbd and custom pool Stefan Priebe
2012-06-18 22:23 ` Mark Nelson
2012-06-18 22:41 ` Dan Mick
2012-06-19 6:06 ` Stefan Priebe
2012-06-19 6:30 ` Stefan Priebe - Profihost AG
2012-06-19 4:41 ` Alexandre DERUMIER
2012-06-19 6:32 ` Stefan Priebe - Profihost AG
2012-06-19 13:01 ` Mark Nelson
2012-06-19 13:14 ` Stefan Priebe - Profihost AG [this message]
2012-06-19 14:05 ` bad performance fio random write - rados bench random write to compare? Alexandre DERUMIER
2012-07-02 19:52 ` Gregory Farnum
2012-07-03 7:31 ` Stefan Priebe - Profihost AG
2012-06-19 15:42 ` Heavy speed difference between rbd and custom pool Sage Weil
2012-06-19 16:24 ` Stefan Priebe
2012-06-19 16:27 ` Sage Weil
2012-06-19 16:29 ` Dan Mick
2012-06-20 6:46 ` Stefan Priebe - Profihost AG
2012-06-20 23:21 ` Dan Mick
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