If you want a disaster recovery for a Linux server (Debian here), you can find some very nasty tools on the web. The one I’m using for ages already, is Mondo (and Mindi).
For a Debian 5 Lenny server, go to ftp://ftp.mondorescue.org/debian/ and download the packages mindi, mindi-busybox and mondo. Of course they have some dependencies you’ll lto install together with your downloaded packages.
Once they are installed you can choose between 2 backup types:
By creating a boot-able USB disk, here with a 750GB USK disk:
Boot from that USB disk and you’ll have your server again.
By creating boot-able ISO files, here 4GB DVD ISO files:
Of course, folders /mondo, /mondo/iso and /mondo/tmp have to exist already.
In case you chose for the ISO option, you will find your boot-able ISO files inside /mondo.
Burn them on DVD:
Boot from that DVD in case of a Disaster Recovery, and there you have your server again, just like it was when you took the mondoarchive!
Most important for Disaster Recovery, test it before you need it!!!