From: Dave Chinner <david@fromorbit.com>
To: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Cc: Matthew Whittaker-Williams <matthew@xsnews.nl>, xfs@oss.sgi.com
Subject: Re: XFS hangs and freezes with LSI 9265-8i controller on high i/o
Date: Fri, 15 Jun 2012 22:30:34 +1000 [thread overview]
Message-ID: <20120615123034.GC19223@dastard> (raw)
In-Reply-To: <4FDB1BA6.3030203@itwm.fraunhofer.de>
On Fri, Jun 15, 2012 at 01:25:26PM +0200, Bernd Schubert wrote:
> On 06/15/2012 02:16 AM, Dave Chinner wrote:
> >Oh, I just noticed you are might be using CFQ (it's the default in
> >dmesg). Don't - CFQ is highly unsuited for hardware RAID - it's
> >hueristically tuned to work well on sngle SATA drives. Use deadline,
> >or preferably for hardware RAID, noop.
>
> I'm not sure if noop is really a good recommendation even with hw
> raid, especially if the the request queue size is high. This week I
> did some benchmarks with a high rq write size (triggered with
> sync_file_range(..., SYNC_FILE_RANGE_WRITE) ) and with noop
> concuring reads then almost entirely got stalled.
> With deadline read/write balance was much better, although writes
> still had been preferred (with sync_file_range() and without). I
> always thought deadline prefers reads and I hope I find some time
> later on to investigate further what was going on.
> Test had been on a netapp E5400 hw raid, so rather high end hw raid.
Sounds like a case of the IO scheduler queue and/or CTQ being too
deep.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2012-06-15 12:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-11 21:37 XFS hangs and freezes with LSI 9265-8i controller on high i/o Matthew Whittaker-Williams
2012-06-12 1:18 ` Dave Chinner
2012-06-12 15:56 ` Matthew Whittaker-Williams
2012-06-12 17:40 ` Matthew Whittaker-Williams
2012-06-13 0:12 ` Stan Hoeppner
2012-06-13 1:19 ` Dave Chinner
2012-06-13 3:56 ` Stan Hoeppner
2012-06-13 8:54 ` Matthew Whittaker-Williams
2012-06-13 11:59 ` Andre Noll
2012-06-13 12:13 ` Michael Monnerie
2012-06-13 16:12 ` Stan Hoeppner
2012-06-14 7:31 ` Michael Monnerie
2012-06-14 0:04 ` Dave Chinner
2012-06-14 14:31 ` Matthew Whittaker-Williams
2012-06-15 0:16 ` Dave Chinner
2012-06-15 9:52 ` Michael Monnerie
2012-06-15 12:29 ` Dave Chinner
2012-06-15 11:25 ` Bernd Schubert
2012-06-15 12:30 ` Dave Chinner [this message]
2012-06-15 14:22 ` Bernd Schubert
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