Root FS on RAID 1 and Grub

[Nils]

Hi all,

Some time ago I setup a server with the root FS on a RAID 1, using
Linux MD RAID. I also manually setup grub on both drives, so that if
one drive fails, you are still able to boot.

However, when I rebooted the box it was stuck before loading grub and
for first i did not know why. When I then selected the other drive in
the BIOS, it booted again w/o problems. As far as I remeber, I did a
kernel upgrade on it (just ran apt-get update && apt-get dist-upgrade
..) and I think that Ubuntu wrote the entry for the new kernel to just
one disk.

Now to my question: How can I configure Ubuntu so that it sets up the
MBR correctly on both drives, when the kernel is upgraded?

Nils