Comment 1 for bug 136252

I had the same problem when converting from one disk to a RAID-1 setup.

I added a break=mount and tried to start the arrays with "mdadm -A -s", but that didn't work.

The default configuration has a line "DEVICE partitions" in /etc/mdadm/mdadm.conf. This apparently doesn't work.

(All my partitions are listed in /proc/partitions and the major/minor numbers match up to those in /dev)

Adding the ARRAY lines to mdadm.conf and regenerating the initrd image worked for me.

I'm using gutsy 7.10 x86_64 with Linux image 2.6.22-14-generic (all updates installed).