Why Bother With Backups?

Even if a system is maintained by an incredibly meticulous system administrator and restricted to use only by the world's most intelligent users, at some point at least one file will be lost.

Part of a system administrator's job is maintaining the integrity of a system. This does not mean that the system administrator is expected to prevent anything unexpected from happening ever. It means that a good system administrator needs to be aware of possible emergencies and have a plan to deal with them. One of the most basic emergencies is the loss of data.

In a worst case scenario the building that houses the system burns down, and all the data is destroyed. Having a hard drive go bad can also result in a complete loss of data. Partial loss of data can be caused by a number of things from a virus to an accident with rm. In each of these cases the system can be rebuilt, but without a backup it cannot be restored to its original condition.

Backups can also be valuable security tools. Backups can provide a record of key system directories such as /etc, which can be compared with the current state of the directory to check for unauthorized modifications.