backup

Here's a quicky backup script using rsync. I would prefer rdiff-backup, but it wasn't an option for me in this case.

#!/bin/bash

SRV="someserverbackup"
DAY=`date +%a`
BDIR="/storage/backup"
BBDIR="${BDIR}/${DAY}/${SRV}"

rm -rf "${BBDIR}"

/usr/bin/rsync -a --delete --numeric-ids --backup --backup-dir="${BBDIR}" \
	"${SRV}":{/home,/srv,/etc} "${BDIR}/${SRV}"

#end

It gives you 7 days in changed files, ie you can go back in time 7 days.
it's run once per day via cron as root. 

then in ~/.ssh/config

Host someserverbackup
        Hostname 192.168.1.1
        ControlMaster no
        IdentityFile /root/.ssh/someserverbackup_dsa

An easy way to specify a key, works with rdiff-backup and rsync, etc. Saves having to specify the key on the command line, which is different for different applications.

Then on 192.168.1.1 in /root/.ssh/authorized_keys

from="192.168.1.2",command="/usr/local/bin/rsync-only" ssh-dss AAAA...

where 192.168.1.2 is the host where the back up script runs, and you can google 
for the rsync-only script, it does just what it says, restricts that key to rsync
and to the host 192.168.1.2.