Cloning your Debian system

[Viktor Lakics <lakicsv@usa.net>]

I got a crazy idea: if you want to make 100 % sure that you do not
brake your production system, why don't you have an exact copy of
that system before you do an upgrade (or just use that system for
trying out things, which you cannot afford on your system).

I got a spare 2 Gig partition on my system, and I want to give it a
try. I just do not know how to start this? O.K. I could probably do
it with hard disk image program, but then what configuration files
do I have to edit (exept /etc/fstab) after my root partition moves
from /dev/hda8 to /dev/hda7...

Anyone have done it already? All comments and possible ways to do it
are welcome!

Thanks in advance. -- Viktor