Comment 18 for bug 577239

The error message that you get here
"cryptsetup: lvm device name (/dev/disk/by-uuid/...) does not begin with /dev/mapper/" comes due to the fact that the
conf/conf.d/cryptroot in initramfs contains a line with "source=UUID=<uuid>" instead of the intended source="/dev/mapper/<vol-group-path>" if there is a symbolic link from /dev/by /dev/disk/by-uuid/<uuid> to /dev/mapper/<vol-group>. Attaching a cryptsetup patch that fixes this part.

Currently Ubuntu's mdadm faces a few problems in autoassembly. However a assembly based on mdadm.conf with appropriate mdadm array definitions in /etc/mdadm/mdadm.conf (both in real root and initramfs) will help assemble the array at boot time.

I have kept the mdadm fixes for autoassembly to work at: https://edge.launchpad.net/~csurbhi/+archive/lucid?field.series_filter=
(kept in a ppa named lucid)

Note that the uuid needs to be updated for the autoassembly to work at boot time. This can be done by
1) installing the test mdadm ppa.
2) Note your uuid by mdadm --detail --scan
3) update-initramfs
4) try autoassembly by rebooting. This will still fail and you will get to an initramfs prompt. At this time, test if your hostname is set appropriately. If it is, then run "mdadm --assemble -U uuid. Note if your uuid has changed (it should at this point and correspond to your hostname)
3) try rebooting.
Once your uuid has been updated to correspond with your hostname, the autoassembly of the md devices should ideally work. However note that this is a test ppa and yet under testing. Please try at your own risk ;-) and ofcourse let us know if there are any bugs in it if you happen to catch them :-)

For now, the attached patch shall take care of the "/dev/mapper" error message!