<p>That's true about having real time data stored to RAID. That is why it's imperative to have a data management plan. Having daily, weekly, and/or monthly backups ensure recovery at any level of corruption. Daily backups ensure the "oops I deleted a file" can be restored and weekly if you discover that "oops" later or discover a virus.<br>
RAID works best at handling data over multiple disks and maybe not so much as "THE" backup strategy. Granted it is a storage solution.<br>
RAID (depending on the level) mitigates a failed drive, or as Eric brought up, failing sectors. It distributes or mirrors sectors to alternate sectors spanning multiple disks.<br>
Ray as you stated, if a virus were to propagate through a RAID'd storage array, the cleanup would be lengthy at best and a total loss at worst.<br>
My point is this, backups should be implemented to negate a total catastrophe. If you're running RAID, taking a weekly backup of the data on the RAID disks should be backed up off site. Be it cloud or another drive.<br>
Also, to save drive space and if your backup software can handle it, implementing snapshots can greatly decrease the size of data being retained. Although, snapshots work best on VM's.</p>