From: Ric Wheeler <ricwheeler@gmail.com>
To: Chris Friesen <chris.friesen@genband.com>
Cc: Neil Brown <neilb@suse.de>, linux-raid@vger.kernel.org
Subject: Re: RFC: use TRIM data from filesystems to speed up array rebuild?
Date: Tue, 04 Sep 2012 15:11:26 -0400 [thread overview]
Message-ID: <5046525E.10500@gmail.com> (raw)
In-Reply-To: <50464322.3010509@genband.com>
On 09/04/2012 02:06 PM, Chris Friesen wrote:
>
> Hi,
>
> I'm not really a filesystem guy so this may be a really dumb question.
>
> We currently have an issue where we have a ~1TB RAID1 array that is mostly
> given over to LVM. If we swap one of the disks it will rebuild everything,
> even though we may only be using a small fraction of the space.
>
> This got me thinking. Has anyone given thought to using the TRIM information
> from filesystems to allow the RAID code to maintain a bitmask of used disk
> blocks and only sync the ones that are actually used?
>
> Presumably this bitmask would itself need to be stored on the disk.
>
> Thanks,
> Chris
>
Device mapper has a "thin" target now that tracks blocks that are allocated or
free (and works with discard).
That might be a basis for doing an focused RAID rebuild,
Ric
next prev parent reply other threads:[~2012-09-04 19:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-04 18:06 RFC: use TRIM data from filesystems to speed up array rebuild? Chris Friesen
2012-09-04 19:11 ` Ric Wheeler [this message]
2012-09-04 20:24 ` NeilBrown
2012-09-04 22:59 ` Ric Wheeler
2012-09-06 17:17 ` Benjamin ESTRABAUD
2012-09-06 18:42 ` David Brown
2012-09-07 9:23 ` Benjamin ESTRABAUD
2012-09-04 20:21 ` NeilBrown
2012-09-04 20:28 ` Chris Friesen
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