I think I messed up pretty bad. On my old system, I had 2 identical drive that were assembled with mdadm as a MD RAID 10 with a "far" layout.

When building my new system and migrating the two disks, I had a total brain fart, and instead of doing assemble and scan, I ran the following command:

mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdd1 /dev/sde1

When /dev/md0 wouldn't mount, I quickly realized that this was not what I intended, but the damage was done, as mdadm had started the sync. I have stopped mdadm (mdadm --stop /dev/md0), and now I can't mount the drives individually (unknown filesystem type 'linux_raid_member'), and parted doesn't see any filesystem on the partitions of the individual drives.

Is there a way to recover the data from either drive, or did mdadm completely destroy both drives in an unrecoverable way?

  • 1
    Time to go to your backups. – Michael Hampton Apr 16 '14 at 2:54
  • @MichaelHampton I figured as much, I am mostly interested in seeing if there's a way that's less trouble than going through my backups – Fred Apr 16 '14 at 3:10
  • 2
    Not really. At this point you're in data-recovery land, which is much more trouble than restoring from backups. – Michael Hampton Apr 16 '14 at 3:14

Creating a raid array resyncs, but does not zero. If the new array happens to be in the same location (likely), and the same type (raid level and superblock type), your data should be readable. Im not aware of the 'far' layout and how it affects your specific case.

  • OP said that the new array did not mount, though? – Håkan Lindqvist Jul 25 '19 at 23:53
  • Right, sorry i missed that. Fred, try creating the original RAID 10 with far layout and then checking for partitions. You'd need to be careful to use the same superblock version as before. – Austin Dixon Jul 26 '19 at 1:02

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