I've used Dell Perc RAID controllers in the past. In those systems, the (hardware) RAID controller usually has an onboard battery backup system that stores the cache state in the event of a sudden power interruption. This is critical to prevent file system corruption.
Our organization is now getting Synology DS36xx NAS boxes, and I'm trying to figure out if there is an equivalent battery backup technology for the RAID those systems use. Is there? Or if not, is there something about the way their RAID works that guards against corruption from sudden power failures?
(Note: yes, we're putting the NAS systems on UPS battery backup. But batteries only last for a limited time, and there is always the risk of failure even with a UPS.)