Comment 0 for bug 880646

I have two identical disks set up in a fake RAID configuration through the PC BIOS, over which a LVM2 volume where all my partitions live except /boot, which is on its dedicated RAID partition.

After the upgrade to 11.04, when doing a cold restart, /dev/dm-* files aren't found, so the booting halts with an error. Stock 11.04 kernel is used as per uname:
Linux rihad 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

Apparently the new kernel also messes up the RAID configuration, because the array members are then shown as OFFLINE in the BIOS making the disks unusable, and nothing short of a cold restart brings them back to life.

Fortunately I was wise enough to have saved the previous distro's kernel vmlinuz-2.6.35-28-generic in my GRUB menu, booting into which can correctly initialize the LVM2/DM subsystem, and then after doing a warm reboot into the newer kernel everything works. So I must do a two-phased boot every morning, which sucks.