From: Dave Chinner <david@fromorbit.com>
To: Michael Monnerie <michael.monnerie@is.it-management.at>
Cc: John Bokma <contact@johnbokma.com>,
Stan Hoeppner <stan@hardwarefreak.com>,
xfs@oss.sgi.com
Subject: Re: 30 TB RAID6 + XFS slow write performance
Date: Thu, 21 Jul 2011 09:01:26 +1000 [thread overview]
Message-ID: <20110720230126.GH9359@dastard> (raw)
In-Reply-To: <201107201604.33419@zmi.at>
On Wed, Jul 20, 2011 at 04:04:31PM +0200, Michael Monnerie wrote:
> On Mittwoch, 20. Juli 2011 Stan Hoeppner wrote:
> > I thought this was packing multiple small files into
> > a single stripe write, which you just explained XFS does not do.
>
> This is interesting, I jump in here. Does that mean that if I have a XFS
> volume with sw=14,su=64k (14*64=896KiB) that when I write 10 small files
> in the same dir with 2KB each, each file would be placed at a 896KiB
> boundary?
No, they'll get sunit aligned but default, which would be on 64k
boundaries.
> That way, all stripes of a 1GB partition would be full when
> there are roughly 1170 files (1170*896KiB ~ 1GB). What would happen when
> I create other files - is XFS "full" then, or would it start using sub-
> stripes? If sub-stripes, would they start at su (=64KiB) distances, or
> at single block (e.g. 4KiB) distances?
It starts packing files tightly into remaining free space when no
free aligned extents are availble for allocation in the AG.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2011-07-20 23:01 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-18 19:58 30 TB RAID6 + XFS slow write performance John Bokma
2011-07-19 0:00 ` Eric Sandeen
2011-07-19 8:37 ` Emmanuel Florac
2011-07-19 22:37 ` Stan Hoeppner
2011-07-20 0:20 ` Dave Chinner
2011-07-20 5:16 ` Stan Hoeppner
2011-07-20 6:44 ` Dave Chinner
2011-07-20 12:10 ` Stan Hoeppner
2011-07-20 14:04 ` Michael Monnerie
2011-07-20 23:01 ` Dave Chinner [this message]
2011-07-21 6:19 ` Michael Monnerie
2011-07-21 6:48 ` Dave Chinner
2011-07-22 6:10 ` Michael Monnerie
2011-07-22 18:05 ` Stan Hoeppner
2011-07-22 23:10 ` Dave Chinner
2011-07-24 6:14 ` Stan Hoeppner
2011-07-24 8:47 ` Michael Monnerie
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