Comment 9 for bug 968074

Everything below was done on precise:

I do agree that the standard partitionable mdadm raid devices (/dev/md_dNNpXX) were not supported in precise, but now are supported with the version from -proposed.

But please note that even though I created /dev/md_d1, /dev/md_d1p1 and /dev/md_d1p2 the device names have changed after the reboot to /dev/md127, /dev/md127p1, /dev/md127p2 which is interesting. As long as you use UUID to mount filesystems everything should be fine, or create the md device with stable names e.g. /dev/md/myraid with partitions /dev/mdmyraid1 /dev/mdmyraid2, as those names will stay stable.