From: Neil Brown <neilb@suse.de>
To: Brett Maton <Brett.Maton@simplyhealth.co.uk>
Cc: linux-raid@vger.kernel.org
Subject: Re: mdadm break / restore soft mirror
Date: Thu, 13 Dec 2007 12:19:17 +1100 [thread overview]
Message-ID: <18272.34965.638276.892803@notabene.brown> (raw)
In-Reply-To: message from Brett Maton on Wednesday December 12
On Wednesday December 12, Brett.Maton@simplyhealth.co.uk wrote:
> Hi,
>
> Question for you guys.
>
> A brief history:
> RHEL 4 AS
> I have a partition with way to many small files on (Usually around a couple of million) that needs to be backed up, standard
>
> methods mean that a restore is impossibly slow due to the sheer volume of files.
> Solution, raw backup /restore of the device. However the partition is permanently being accessed.
>
> Proposed solution is to use software raid mirror. Before backup starts, break the soft mirror unmount and backup partition
>
> restore soft mirror and let it resync / rebuild itself.
>
> Would the above intentional break/fix of the mirror cause any problems?
No, it should work fine.
If you can be certain that the device that you break out of the mirror
is never altered, then you could add an internal bitmap while the
array is split and the rebuild will go much faster.
However even mounting a device readonly will sometimes alter the
content (e.g. if ext3 needs to replay the journal) so you need to be
very careful.
NeilBrown
next prev parent reply other threads:[~2007-12-13 1:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-12 22:08 mdadm break / restore soft mirror Brett Maton
2007-12-12 22:27 ` Richard Scobie
2007-12-13 1:19 ` Neil Brown [this message]
2007-12-13 4:00 ` Jeff Breidenbach
2007-12-13 4:16 ` Neil Brown
2007-12-14 7:40 ` Jeff Breidenbach
2007-12-14 9:08 ` Neil Brown
2007-12-14 19:13 ` Jeff Breidenbach
2007-12-14 19:52 ` Jeff Breidenbach
2007-12-13 22:45 ` Bill Davidsen
-- strict thread matches above, loose matches on Subject: below --
2007-12-13 7:02 Brett Maton
2007-12-14 0:04 ` Neil Brown
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