I have a 3 disk raid 5 where 2 disks have been accidentally formatted with the xfs file system.
The disks are partitioned into 6 partitions - sd[a,b,c][1-6]
The disks were present in a Buffalo Terrastation NAS. I just powered down the NAS, removed the disks and booted up a Linux live CD with the disks attached.
mdadm --examine /dev/sda6 reports nothing mdadm: No md superblock detected on /dev/sda6 mdadm --examine /dev/sdb6 reports nothing mdadm: No md superblock detected on /dev/sdb6 mdadm --examine /dev/sdc6 reports nothing mdadm: No md superblock detected on /dev/sdc6
By accident sda6, sdb6 and sdc6 have been formatted with to the xfs file system.
I mounted it as read-only for testing. It is empty - just 5 empty folders created by default by the Buffalo NAS. No real data has been written so far to the disks.
I replaced one of the disks from the raid 6 weeks again and kept it:
mdadm --examine /dev/sdd6 reports raid5 with 4 disks.
So this is the only disk, that still knows there was a raid. Is there a change to restore the superblocks and assemble the raid again?