RAID
RAID cannot protect the data on the array. A RAID array has one file system. This creates a single point of failure. There are many things that can happen to this file system other than physical disk failure. RAID cannot defend against these sources of data loss. RAID will not stop a virus from destroying data. RAID will not prevent corruption. RAID will not save data when a user modifies it or deletes it by accident. RAID does not protect data from hardware failure of any component besides physical disks. RAID does not protect data from natural or man made disasters such as fires and floods. To protect data, it must be backed up to removable media, such as DVD, tape, or an external hard disk. The backup must be kept in a different place. RAID alone will not prevent a disaster, when (not if) it occurs, from turning into data loss. Disasters cannot be prevented, but backups allow data loss to be prevented.