Configuring grub2 on a backup disk

[John Little]

> I'm running Ubuntu 10.04, and planning to upgrade. Before I do, though,
> I want to make sure my backup/restore processes work. My backups, of
> course, have been running since I first installed 10.04, but it's only a
> restore that can demonstrate that they have been running successfully.
>
> And I've found a problem. I don't know how to get grub2 configured
> correctly, on the restored disk.
> ...

> Any ideas?

I did something like this once, but I don't understand your set up, or
exactly what you're trying to do.  However, here's two things I
learned that may be very relevant.

Firstly, grub2 by default uses UUIDs to identify partitions to boot
from, and if you clone a partition, or restore its image from a
backup, you've cloned the UUID.  If both partitions are present in a
system, grub will not find one of them, and sanity will be elusive.
One can use

    tune2fs -U random

to set a new UUID on a ext2, ext3 or ext4 partition.

Secondly, you may need to use the chroot method to reinstall grub on
the restored disk.  Having an Ubuntu live CD (for the same version and
architecture) may be handy, and this how-to may tell what you need:

http://ubuntuforums.org/showthread.php?t=1581099

Regards, John Little