====== Recover RAID mirror disk from image file ======

===== Scenario =====

Failing hard disk in a 2 disk mirror, suspect disk problems as both disks seemed to suffer failures at the same time.

dd-recover used to copy each partition to an image file which needed mounting to allow data to be copied off for a holding filesystem.

===== Solution =====

You can't just mount the image file on it's own as it's part of a mirror (mdadm), so this won't be any good:- ''mount -o ro partition1_file.raw /tmp/partition1''

This needs to be assembled to a single disk mirror:-
<code>
# mdadm --assemble --run /dev/md1 partition1-complete.raw 
</code>
But this won't work either as the raw file is not a device mdadm recognises, it needs to be mounted as a loop device with ''losetup'' and then assembled with ''mdadm'':-
<code>
# losetup /dev/loop1 partition1-complete.raw 
# mdadm --assemble --run /dev/md1 /dev/loop1 
# cat /proc/mdstat
</code>
But for some reason, this command does not create a ''/dev/md1'' device, it creates a ''md127'' which it still thinks should be running, so the assemble command fails again.
You need to stop the mirror array and then assemble it:-
<code>
# mdadm --stop /dev/md127
# mdadm --assemble --run /dev/md127 /dev/loop1
# cat /proc/mdstat 
# mount /dev/md127 /mnt/p1
</code>
And finally, you can mount the raw image as a filesystem.




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