From: Mark Nelson <mark.nelson@inktank.com>
To: James Harper <james.harper@bendigoit.com.au>
Cc: "ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: poor write performance
Date: Fri, 19 Apr 2013 09:50:43 -0500 [thread overview]
Message-ID: <517159C3.5030100@inktank.com> (raw)
In-Reply-To: <6035A0D088A63A46850C3988ED045A4B4D739E99@BITCOM1.int.sbss.com.au>
On 04/19/2013 06:09 AM, James Harper wrote:
> I just tried a 3.8 series kernel and can now get 25mbytes/second using dd with a 4mb block size, instead of the 700kbytes/second I was getting with the debian 3.2 kernel.
That's.... unexpected. Was this the kernel on the client, the OSDs, or
both?
>
> I'm still getting 120kbytes/second with a dd 4kb block size though... is that expected?
that's still quite a bit lower than I'd expect as well. What were your
fs mount options on the OSDs? Can you try some rados bench read/write
tests on your pool? Something like:
rados -p <pool> -b 4096 bench 300 write --no-cleanup -t 64
rados -p <pool> -b 4096 bench 300 seq -t 64
with 2 drives and 2x replication I wouldn't expect much without RBD
cache, but 120kb/s is rather excessively bad. :)
>
> James
>
Mark
next prev parent reply other threads:[~2013-04-19 14:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-18 11:46 poor write performance James Harper
2013-04-18 12:15 ` Wolfgang Hennerbichler
2013-04-18 23:11 ` James Harper
2013-04-20 10:52 ` Harald Rößler
2013-04-20 11:12 ` James Harper
2013-04-20 21:04 ` Jeff Mitchell
2013-04-18 13:43 ` Mark Nelson
2013-04-18 16:46 ` Andrey Korolyov
2013-04-18 17:01 ` Mark Nelson
2013-04-18 23:23 ` James Harper
2013-04-19 7:21 ` James Harper
2013-04-19 7:30 ` James Harper
2013-04-19 11:09 ` James Harper
2013-04-19 14:50 ` Mark Nelson [this message]
2013-04-20 0:33 ` James Harper
2013-04-20 1:30 ` James Harper
2013-04-21 13:52 ` Mark Nelson
2013-04-22 5:32 ` James Harper
2013-04-22 11:34 ` Mark Nelson
2013-04-22 11:40 ` James Harper
2013-04-21 17:56 ` Sylvain Munaut
2013-04-21 23:04 ` James Harper
2013-04-22 8:34 ` Sylvain Munaut
2013-04-22 11:34 ` James Harper
2013-04-22 11:39 ` Mark Nelson
2013-04-22 11:48 ` James Harper
2013-04-22 12:01 ` Mark Nelson
2013-04-22 13:47 ` Mark Nelson
2013-04-22 15:20 ` Sage Weil
2013-04-22 15:35 ` Sylvain Munaut
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