Debian Configuration :: Copy Full System To Another Machine

I am setting up a mail server on debian. Once it's done, I'd like to have an indentical server on another machine, where debian will also be installed. The solution has to be hardware agnostic, so source machine is different than destination machine. I was reading on some wiki page that one can simply copy the root filesystem via rsync to the computer that he'd like to install the system on, then chroot to it and test if everything works. I'm guessing I'd have to change a couple things before, like :

- The network config
- The /etc/fstab file (disks and partitions may be different)

This article is about using rsync to transfer a copy of your "/" tree, excluding a few select folders. This approach is considered to be better than disk cloning with dd since it allows for a different size, partition table and filesystem to be used, and better than copying with cp -a as well, because it allows greater control over file permissions, attributes, Access Control Lists (ACLs) and extended attributes. [1]