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From: NeilBrown <neilb@suse.de>
To: Keith Keller <kkeller@wombat.san-francisco.ca.us>
Cc: linux-raid@vger.kernel.org
Subject: Re: recovery from multiple failures
Date: Mon, 9 Jan 2012 16:13:11 +1100	[thread overview]
Message-ID: <20120109161311.77897c30@notabene.brown> (raw)
In-Reply-To: <qa8qt8xi1r.ln2@goaway.wombat.san-francisco.ca.us>

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On Sun, 08 Jan 2012 20:51:06 -0800 Keith Keller
<kkeller@wombat.san-francisco.ca.us> wrote:

> On 2012-01-09, Keith Keller <kkeller@wombat.san-francisco.ca.us> wrote:
> > md/raid:md0: cannot start dirty degraded array.
> 
> Upon further reading (specifically man md), it looks like this is the
> tail reason for the array not starting--the kernel will refuse to start
> arrays in this condition.  If I'm reading the docs and other posts
> accurately, it seems like I can use a kernel parameter (since this isn't
> my /, I should also be able to unload and re-load the md module) to
> force the kernel to start the array, at which point in theory I should
> be able to work with it (including, ultimately, an xfs_repair if
> needed).  But OTOH, it seems like this parameter applies only to / on
> mdraid, and --force should have started the array, so I'm not really
> sure what to make of it.
> 
> I've posted this before, but the kernel I'm using is fairly recent,
> 2.6.39-4.el5 from ELrepo.
> 
> --keith
> 

--assemble --force certainly should start dirty/degraded array.
There was a bug a while back where it didn't.  Maybe you should try a newer
mdadm.

Alternately:
 
   echo 1 > /sys/module/md_mod/parameters/start_dirty_degraded 


and try again.  That is an easy way to set the module parameter after the
module is loaded.

NeilBrown

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  reply	other threads:[~2012-01-09  5:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-08 20:12 recovery from multiple failures Keith Keller
2012-01-09  0:11 ` Phil Turmel
2012-01-09  1:08   ` Mikael Abrahamsson
2012-01-09  1:43   ` Keith Keller
2012-01-09  1:58     ` Keith Keller
2012-01-09  4:51     ` Keith Keller
2012-01-09  5:13       ` NeilBrown [this message]
2012-01-09  6:23         ` Keith Keller

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