Some are learning that RAID is NOT a backup solution the hard way : Data Loss Dooms Blog Hosting Service « Data Center Knowledge. Explained really simply, RAID mirrors one disk to another (or multiple disks to multiple disks) but a mirror is a mirror ! So if you mess on a disk, the mess will be replicated to the other disks. Remember that you should always think about archives and external backups if your content is valuable! Even if you are using RAID !