# grub grub> find /grub/stage1 (hd0,0) (hd1,0) (hd2,0) grub> device (hd0) /dev/sda grub> root (hd0,0) grub> setup (hd0) grub> device (hd0) /dev/sdb grub> root (hd0,0) grub> setup (hd0) grub> device (hd0) /dev/sdc grub> root (hd0,0) grub> setup (hd0) grub> quit
With this you should be able to now boot from any of the disks in the RAID-1 array, no matter what boot order you set in the BIOS.
For safety, I suggest using UUIDs in your /etc/fstab file for your /boot and / (root) partitions. This way the machine will boot off the UUIDs of the file systems, even if mdadm (software RAID) decides to renumber your /dev/md# devices. Note: This is the default behavior in RHEL 6 / CentOS 6.