[Discuss] How do you backup "/" with rsync?

[John Blomfield]

I am not sure if this is what your looking for but I mentioned this 
before when talking about recovering a damaged MBR.  I am assuming here 
that you have backed up your /boot directory containing grub onto your 
external HD along with everything else.  Then you need to recreate the 
MBR on the external HD, so boot the system with a "Rescue CD" containing 
the usual Linux utilities, which will find your two Linux installations, 
one on your internal HD and one on your external HD. Then:

# chroot /mnt/sysimage   - this gives you access to your installation 
image, this name could be different with different distributions.( 
Fedora in this case, the Fedora rescue disc works with any distribution)

Then do the following:
   # login
    login: root
   passwd: ******
   # cd /boot
   /boot# grub
   grub > find /boot/grub/stage1
   "response will be something like " (hd0, 0) (hd1, 0)
   -what this tells you is that stage1 of grub has been found in two 
partitions, one of which is the partition (hd0, 0) or sda1 your internal 
HD, and the other partition (hd1, 0) or sdb1 your external HD.  Now 
type, ( note the > is the Grub prompt)
    > root (hd1, 0)
   > setup (hd1)
   > quit

This will make your external HD bootable with a grub menu, as well as 
your internal HD.  Now all you have to do is to change the BIOS to 
choose which one you want to boot from.

John Blomfield