I have a Synology 213 ordered along with 2 2TB drives. I'm using the NAS strictly for file storage and backup, so I don't think I'll use a RAID setup. Instead, I'd like to use one drive for storage and use the other for backup. It's my understanding that this isn't the best use of RAID since there are numerous situations in which RAID isn't exactly a reliable backup solution (e.g. user error, deleting files by accident). I've read that you can externally hook up a hard drive via USB and use the backup software built into the 213, but can you also backup to an internal drive in the second bay? Or will I need to buy an external closure for my second hard drive and hook it up via USB?