Ubuntu 12.04 64. Hardware failure (motherboard) led me to build a new machine, and I took the opportunity to do a fresh install of Ubuntu (first one was a learning experience). I moved the raid disks over and am seeing them in Disk Utility as /dev/sdb and /dev/sdc with their volumes listed as "RAID Component".

However, when I try to mount them like so

sudo mdadm --assemble /dev/md0 /dev/sdb /dev/sdc

I get this error

mdadm: Cannot assemble mbr metadata on /dev/sdb
mdadm: /dev/sdb has no superblock - assembly aborted

Any ideas?

2 Answers 2


Solution: I followed the instructions found here: Move RAID1 to new machine

In effect, I had to disconnect the drives during the installation process, then the system detected them properly once it was up and running.


The problem may have been not addressing the RAID partitions on the devices instead of the device. Using:

mdadm --examine /dev/sdb
mdadm --examine /dev/sdb1

you can check for which superblock is the one you want for your raid.

Then, you have to choose the actual block, e.g.:

mdadm --assemble /dev/md0 /dev/sdb2 /dev/sdc2

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