From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wols Lists <antlists@youngman.org.uk>
Subject: Re: raid md126, md127 problem after reboot, howto fix?
Date: Sun, 08 Feb 2015 21:29:53 +0000
Message-ID: <54D7D551.2030800@youngman.org.uk>
References: <54D7B317.5010809@gmail.com>
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To: Marc Widmer <metafor@gmail.com>, linux-raid@vger.kernel.org
List-Id: linux-raid.ids

On 08/02/15 19:03, Marc Widmer wrote:
> Hi List
> 
> I have no deep unterstand about raids, beside setting them up initially and
> replacing disks if needed. So this error has never happened to me before:
> 
> After a reboot i have a really strange behaviour on my server. Disks are
> not marked faulty, but raid is "fallend apart".
> 
> /proc/mdstat shows me:
> 
> md126 : active raid1 sda1[0]
>       10485696 blocks [2/1] [U_]
> 
> md127 : active raid1 sda2[0]
>       721558464 blocks [2/1] [U_]
> 
> md1 : active raid1 sdb1[1]
>       10485696 blocks [2/1] [_U]
> 
> md2 : active raid1 sdb2[1]
>       721558464 blocks [2/1] [_U]
> 
> wished would be something similar to:
> md1 : active raid1 sdb1[1] sda1[0]
>       10238912 blocks [2/2] [UU]
> 
> md2 : active raid1 sdb2[1] sda2[0]
>       1942746048 blocks [2/2] [UU]
> 
> Currently only md1, md2 are running. nmon shows me, that only disks sdb is
> active, sda is not doing anything.
> 
> I run debian squeeze.

What version of mdadm are you running? 3.2.6 or thereabouts?
> 
> I am a bit concerned what to do, because at the moment i run on one disk
> only and if things go wrong i end up with a server not running (downtime)
> and possible data loss (beside backups).
> 
> Any ideas what i should do? Howto put the raid back together, possibly in
> live mode, without rebooting in rescue mode and risk long downtime?
> 
> Any help would be greatly appreciated as by now the only thing i had to do
> was resyncing a disk after usual hd crash.
> 
The reason I ask is this looks like a bug I had - if I'm right it's a
known problem and you need to upgrade mdadm.

Cheers,
Wol