Work in progress.
A simple way to backup your entire linux machine is just to create a tar all files
tar -cvzpf backup.tar.gz --directory=/ --exclude=proc --exclude=sys --exclude=dev --exclude=run --exclude=tmp --exclude=boot .
We set the directory to create the archive from to / and include everything in the archive with the
. at the end. Also exclude directories like /dev or /sys, which are machine or OS specific and don't contain any of our files.