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From: Kay Sievers <kay.sievers@vrfy.org>
To: linux-hotplug@vger.kernel.org
Subject: Re: vol_id and RAID1 members
Date: Tue, 24 Jan 2006 23:55:23 +0000	[thread overview]
Message-ID: <20060124235523.GA22454@vrfy.org> (raw)
In-Reply-To: <20060124223036.GA16374@wonderland.linux.it>

On Tue, Jan 24, 2006 at 11:30:36PM +0100, Marco d'Itri wrote:
> Today one of the disks in a mirrored RAID array failed, and I noticed
> that the /dev/disk/by-label/ link had changed from md2 to hda6, the
> failed device.
> By looking at /dev/.udev/db/ I determined that vol_id returned
> ID_FS_LABEL_SAFE=home for both md2 and hda6, because hda6 is not part of
> the RAID array anymore and obviously both devices have identical file
> system superblocks.
> 
> Having the by-label link change after a reboot is a big problem which
> could easily cause data loss, but I am not sure about how to fix it.
> Should vol_id be modified to look for the RAID superblock and if one is
> present ignore the file system superblock?

Sure, vol_id does look at the raid signature and ignores it, that's the
reason your raid did not show up in the past. Does the degration of the
device means that the raid signature is no longer valid?

What does the debug of vol_id print if run on the raid member? If it does
not show anything intersting, compile udev with DEBUG=true and run vol_id
with UDEV_LOG=7.

Kay


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  reply	other threads:[~2006-01-24 23:55 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-24 22:30 vol_id and RAID1 members Marco d'Itri
2006-01-24 23:55 ` Kay Sievers [this message]
2006-01-27 13:06 ` Marco d'Itri
2006-01-27 16:02 ` Kay Sievers
2006-01-27 16:35 ` Marco d'Itri
2006-01-27 16:48 ` Kay Sievers
2006-01-27 16:56 ` Marco d'Itri

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