From: Christoph Hellwig <hch@infradead.org>
To: Steven Swanson <swanson@cs.ucsd.edu>
Cc: xfs@oss.sgi.com
Subject: Re: Does XFS ever relocate extents after they are on disk?
Date: Fri, 11 Mar 2011 05:09:36 -0500 [thread overview]
Message-ID: <20110311100936.GA11879@infradead.org> (raw)
In-Reply-To: <903E14DC-D9EA-4BDC-8D43-FBB9AB4127BC@cs.ucsd.edu>
On Thu, Mar 10, 2011 at 11:55:21PM -0800, Steven Swanson wrote:
> I have simple question that I'm having trouble finding a concrete answer for:
>
> Does XFS ever relocate a file or one of its extents once it's been written to disk? For instance, does the file system ever decide to reorganize extents to reduce fragmentation.
>
> I've read through all the documentation I can find, and everything points to using an external de-fragmentation tool, which suggests that XFS won't do it autonomously, but for the project we are working on it would be useful to know for certain when and under what conditions XFS might decide to move an extent that's already been written.
XFS kernel code will never move the written extents by itself. The xfs_fsr
tool can instruct the kernel to move extents by the swapext ioctl, and
it can be run through a cron job, although that is usually not required.
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next prev parent reply other threads:[~2011-03-11 10:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-11 7:55 Does XFS ever relocate extents after they are on disk? Steven Swanson
2011-03-11 10:09 ` Christoph Hellwig [this message]
2011-03-11 22:29 ` Steven Swanson
2011-03-14 10:36 ` Christoph Hellwig
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