Originally Posted by psmith811
is this true if the /boot partition is on say /dev/md0 ?
Yes, /boot exists on the md0 but only the first disk will have Grub loaded in the MBR. You need to install Grub to the MBR of the second disk also if you want to be able to reboot the system should the first disk fail.
You just need to do a grub-install on both hd0 and hd1.