Sometimes when my Stora NAS gets rebooted the array fails to mount and I get
/dev/md0 can't read superblock
To correct this I do the following:
- Try mount /dev/md0 (you probably tried this and got the above error)
- If that refuses to repair then do
xfs_repair -L /dev/md0
No guarantees this won’t screw things up for you but it works for me.