Edit: These information work for Ubuntu Breezy. Things may have changed with Dapper Drake
Most cheap hardware RAID controllers such as the VIA VT6421 are not purely hardware RAID systems, but should be seen as semi-soft, or FakeRAID controllers.
In order to install an Operating System on a FakeRAID array, it is thus necessary to setup a few things, since the underlying array is not completly transparent to the Operating System.
This short article, based on the Ubuntu Wiki FakeRaid HOWTO explains how to install Ubuntu Linux on such a FakeRAID array.
First of all, be aware that is it not currently possible (well, it is, actually, but one would have to revert to applying hacking changes in the Initial Ramdisk Image, so it is currently better to forget about it) to setup an LVM Volume on top of a FakeRAID array.
Since the Ubuntu Wiki FakeRaid HOWTO already explains how to install Ubuntu on a FakeRAID/0 array, I am just going to highlight the differences for a FakeRAID/1 array here.
The only difference is the creation of the Initial Ramdisk, which should load the dm-mirror module to allow the OS to read / write from the FakeRAID array.
The /etc/mkinitramfs/scripts/local-top/dmraid should be replaced by
case $1 in
# get pre-requisites
modprobe -q dm-mod
modprobe -q dm-mirror
In addition to the dm-mod module, the previous script launches the dm-mirror module. This means that the dm-mirror module should be copied. This is done by adding the line
to the /etc/mkinitramfs/modules file.
The rest of the Ubuntu FakeRaid Howto gives a good explanation of the tasks that should be done in order to configure the FakeRaid array.