From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Michael Monnerie <michael.monnerie@is.it-management.at>, xfs@oss.sgi.com
Subject: Re: XFS mount failuer on RAID5
Date: Sun, 18 Oct 2009 23:55:38 -0400 [thread overview]
Message-ID: <20091019035538.GC18296@infradead.org> (raw)
In-Reply-To: <20091019013018.GQ9464@discord.disaster>
On Mon, Oct 19, 2009 at 12:30:18PM +1100, Dave Chinner wrote:
>
> IIRC, the main reason for 4k sectors on MD RAID5/6 is that changing
> the IO alignment from 4k to 512 byte IOs (i.e. sub-page sized)
> causes MD to flush and invalidate the stripe cache. Hence every
> time XFS writes a super block, AGF, AGFL or AGI, things go much
> slower because of this flush/invalidate. By setting the sector size
> to 4k, the SB/AGF/AGFL/AGI are all 4k in size and hence IO alignment
This should not happen anymore with 2.6 series kernels.
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next prev parent reply other threads:[~2009-10-19 3:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-16 3:09 XFS mount failuer on RAID5 hank peng
2009-10-16 3:09 ` hank peng
2009-10-16 8:19 ` Michael Monnerie
2009-10-16 15:27 ` Eric Sandeen
2009-10-17 21:27 ` Michael Monnerie
2009-10-19 1:30 ` Dave Chinner
2009-10-19 3:55 ` Christoph Hellwig [this message]
2009-10-16 8:30 ` Justin Piszcz
2009-10-16 8:30 ` Justin Piszcz
2009-10-16 15:28 ` Eric Sandeen
2009-10-16 15:28 ` Eric Sandeen
2009-10-16 15:55 ` Eric Sandeen
2009-10-16 15:55 ` Eric Sandeen
2009-10-19 0:54 ` hank peng
2009-10-19 0:54 ` hank peng
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