Comment 60 for bug 531240

If you still have the vm setup, you could just try to boot the text installer media again, enter the rescue mode and see how it wants to mount the existing raid disks (not degraded, both present) in the vm. That's where it used to always happen. Oherwise, only occasionally during normal reboots.

> When trying to boot with one disk missing, the system would not boot

Right, after way too many release cycles with the unmaintained mdadm modifications in ubuntu, I moved upstream.