Karmic: MD RAID doesn't work

[darren]

Upgraded AMD64 Kubuntu Jaunty to Karmic using update-manager. System cannot find the root partition and drops from GRUB to busybox.

Partition layout:
2 x 250GB SATA drives set to IDE (non RAID) in the BIOS.
/dev/sda1 - /boot ext3
/dev/sda2 - md0
/dev/sda3 - md1

/dev/sdb1 - swap
/dev/sdb2 - md0
/dev/sdb3 - md1

/dev/md0 - /home xfs
/dev/md1 - / ext3

I've got the latest Karmic live CD, installed afresh and the same thing happens. This time the error is:
ALERT! /dev/disk/by-uuid/xxxx-foo-bar does not exist. Dropping to a shell!

ls /dev/disk/by-uuid only shows 2 disks which I assume are the physical disks. cat /proc/partitions only shows the /dev/sda / /dev/sdb partitions, no MD or dm- devices.

I know this mainboard has Nvidia fakeraid. Perhaps the new DMRAID support in Karmic is messing things up?

Let me know any information you require (I can only get to busybox prompt or boot a live CD though)
Cheers

[Sander van Grieken (sander-vangrieken)]

I had the same problem when upgrading to karmic RC1

My setup :

/dev/sd[ab]1 - software raid1 /boot
/dev/sd[ab]5 - software raid1 LVM vg
/dev/sd[ab]6 - software raid0 LVM vg

root, swap, tmp are on the LVM volumes

The initrd dropped me to a shell at boot. The cause seems to be dmraid (fakeraid), because when I removed it (using a livecd) and regenerated the initrd I could boot again.

If dmraid is installed and present in the initrd there are only /dev/sd[ab] device nodes under /dev, no partition device nodes, so it seems dmraid (fakeraid) claims the disks before mdadm (softraid) can claim them.

Possibly useful information:
- I don't know if I had dmraid installed under Jaunty. Probably not.
- I have an nvidia chipset, fakeraid disabled