See http://alioth.debian.org/projects/rootraiddoc/ for some docs
regarding root on raid. I don't know about raidtools2, but mdadm may
operate without config file at all, if you know what're you doing. See
man mdadm, it contains all you need to know. For example, assuming you
have two drives /dev/hda and /dev/hdc having two partitions part1
and part2 of type 0xfd (raid autodetect) on each drive. Than to create raid1,
mirror with mdadm you do next:
mdadm --create /dev/md/0 --level raid1 --raid-devices 2 --spare-devices 0
/dev/hda1 /dev/hdc1