Problem wth RAID1 mount

Historically I had RAID1 with two disks on NAS staorage device Thecus N2200Plus. One disk in raid died, replaced with new one of the same model, but Thecus appears unable to rebuild the raid and there’s no access to OS on Thecus.
I really need to recover data from remaining disk

Here’s list of actions done:

  1. remaining disk from Thecus raid plus new one connected to Linux openSUSE 12.1
  2. RAID1 re-essembled (become /dev/md126 with data and /dev/md126 with swap), remaining disk - /dev/sdd, new disk /dev/sde
  3. Can see disks and new raid on SUSE, but unable to mount

# mount /dev/mapper/vg0-lv0 /recovery
mount: /dev/mapper/vg0-lv0: can’t read superblock

same as

# mount /dev/md126 /mnt/thecus
mount: unknown filesystem type ‘LVM2_member’

Any ideas or suggestions how to recover data from Thecus raid remaining disk?

Variety of possible problems can cause the issue you describe, IMO just because the error says it’s a “superblock” error that’s only a maybe – The system only interpreted the error as a superblock error.

Try mounting the surviving disk as a broken RAID, IMO you’ll probably have better success doing that.
If you can, then copy/transfer all your data to another disk.
Then, if you wish you can consider re-building your RAID1 on either your NAS (if it’s usable) or using openSUSE which I’d suggest should be done only with caution (consider all implications).
After your RAID has been re-built, then move your data back onto your RAID volume.