If the controller goes out, the data should be safe, right? It wouldn't flip out and write some crazy shit on your disks. You wouldn't be able to seamlessly keep your system going though. With mirror mode, you could just pop in an individual drive and keep it rollin'. That's a good point; you would be down until they sent you a replacement. Is it rare for raid controllers to fail? One solution would be to just keep an extra one on hand. This RAID plan keeps getting more expensive...
Too bad tape drives and media are so expensive. It would be nice to just have it automatically schedule your backups every night.
e; I'm looking at some of the prices for RAID controllers on Newegg. Hole E. Shit.