/etc/mdadm/mdadm.conf should now look something like this:
# Please refer to mdadm.conf(5) for information about this file.
# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes
# automatically tag new arrays as belonging to the local system
# instruct the monitoring daemon where to send mail alerts
# This file was auto-generated on Mon, 26 Nov 2007 21:22:04 +0100
# by mkconf $Id: mkconf 261 2006-11-09 13:32:35Z madduck $
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=72d23d35:35d103e3:2b3d68b9:a903a704
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=a50c4299:9e19f9e4:2b3d68b9:a903a704
ARRAY /dev/md2 level=raid1 num-devices=2 UUID=99fee3a5:ae381162:2b3d68b9:a903a704
8 Preparing GRUB (Part 2)
We are almost done now. Now we must modify /boot/grub/menu.lst again. Right now it is configured to boot from /dev/sdb (hd1,0). Of course, we still want the system to be able to boot in case /dev/sdb fails. Therefore we copy the first kernel stanza (which contains hd1), paste it below and replace hd1 with hd0. Furthermore we comment out all other kernel stanzas so that it looks as follows: