Holler if I'm wrong, but;
Software raid is not a hardware raid. This means the kernel amd the
proper module(s) must load to access the raid drive. Therefore a
software raid cannot be /boot or / since these must be available at
boot. Now it may be possible to have GRUB load the modules but the kernel must
still be available.
Well, I was reading a page by some guy who was using a RAID 1 software mirror for /boot - I was interested but wasn't sure it would be a safe or preferred way to do things. I am not sure how md works exactly, but intuitively if you have a md mirror with an ext3 filesystem on it, shouldn't each mirror component have a valid ext3 fs on it? What I always did was just create /boot fs'es on 2 drives and try to keep them in sync... but the md mirrored /boot idea is interesting.
