- copy the mdadm.conf file in /etc/mdadm to somewhere safe (ie the cloud/Ubuntu One)
- copy /etc/fstab to the same
- Boot with your USB or CD and perform a normal Ubuntu installation*
- Install mdadm from the repositories
- Restore the above files and reboot+
*Be careful when running the installation setup that you do not touch your disks that contain the raid. For me, I wanted to keep /dev/sda-d untouched (my RAID 5 disks), wipe /dev/sde1 and sde2, and install on /dev/sdf1,2. To do this you must select the "Do Something Else" option when presented with the options of how to install Ubuntu. Ensure you format the destination of your /.
+If you changed the location of /, ensure you only copy the portion of fstab that is relevant to your RAID, otherwise you will end up with an unbootable partition because it will be looking at /dev/sd?? for your files instead of where you installed them.
Once you have added these files back, perform
sudo mount -a
To remount your filesystems. As a note, my files are as follows:
# 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
# definitions of existing MD arrays
ARRAY /dev/md0 UUID=9e7ab348:9594fe28:0308d362:1f0077d8
# This file was auto-generated on Thu, 12 May 2011 11:17:06 -1000
# by mkconf $Id$
# /etc/fstab: static file system information.
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sde2 during installation
UUID=c8428ebf-d359-41af-91b5-abaec4867d38 / ext4 errors=remount-ro 0 1
# swap was on /dev/sde1 during installation
UUID=f271aec8-6337-4d13-b296-ed30d0e56da0 none swap sw 0 0
# Mount the RAID drives as Media
/dev/md0 /mnt/Media ext4 defaults 0 0
Ensure you press Enter at the end of that last line, otherwise you'll get an error when performing mount -a due to there being no new line at the end of the file.