RAID arrays are not intended for backup; in a RAID system a corruption problem on one drive will be populated to the redundant part of the system so you will lose data. The purpose of a RAID system is to provide uninterrupted availability such as in a credit approval application where continuous availability is a requirement, not to provide backup.
Spot on but for some reason or other people do think RAID is a backup.
I have my doubts about enterprise class HD's.
My NAS is sleeping most of the time (when I asleep and when I am at the office).
In my case I rather have a HD designed to spin up/down frequently than running 24x7 continuously.
I am using a ReadyNas 4200 RAID 5 which is automatically backed up to another 4200 located in a physically remote location.
Do the same with my Qnaps, RSYNC is a very efficient tool to sync.
