Rules of Computer Backups

1. Independence: Take backup on a different disk than the original. It can be a different hard disk, CD whatever.


2. Distance: Keep the backup disk at a different physical location. The ideal is atleast 5 KM distance. Practically it should be at a different building.


3. Completeness: Take the backup of the entire thing. It may include environment variables, documentation, hand-written notes etc.


4. Verification: Do frequent restoration of backups at a separate machine to be sure that the backups is complete, in working state and can be restored.


5. Security: The backup need to be as much secured as the original. This includes computer and network security.


6. Tailness: As time passes, your periodic backups can pile up and make a huge volume. It do not mean you are allowed to delete the old copies. You must keep all of the copies including the very first, because you never know when and to what extent you have to back track and start anew. Disks are cheap.