Comment 17 for bug 1335642

I came across this while purposely breaking my sw RAID array to test if booting through the mirror disk or degraded array was OK.

Comment #4 worked for me.

ls /dev/mapper on the initram shell really showed that my root device (which is on LVM) was not available before running that udevadm command.

There was another catch that took me over an hour: I starting this by physically removing the sda disk. But later I reinserted it, and keep debugging like that most of the time, without resyncing the arrays, 'cause I wanted it to come up fine in that state. So I when I ran update-initramfs only the files in sdb got updated.

*It took me a while to realize that the boot process was reading the initramfs files from the un-updated re-inserted sda disk.* I then re-synced my /boot and the workaround (#4) worked, duh.