Since disk drives are cheap, backup should be cheap too. Of course it does not help to mirror your data by adding more disks to your own computer because a virus, fire, flood, power surge, robbery, etc. could still wipe out your local data center. Instead, you should give your files to peers (and in return store their files) so that if a catastrophe strikes your area, you can recover data from surviving peers. The Distributed Internet Backup System (DIBS) is designed to implement this vision.