Backups are not optional. Some day your disk will crash or your RAID array will fail to start up. If you have an up-to-date backup, you will simply have a bad day or two. If you don’t have a backup, however, the pain and damage will last much longer.
For backing up larger volumes of data please contact email@example.com, and we can discuss backup strategies and ways to implement plans (e.g. MIT’s TSM).