People seem to run NAS boxes with the mind set that if one drive dies, I always have another copy. Something to keep in mind is, where is your backup strategy if the NAS itself dies? Most NAS operating systems are not your everyday systems, although many are Linux based. What that means is knowing ahead of time how you would access your data in the event of a NAS hardware failure.
For a Linux based system using a file system like EXT3, there are drivers available to allow your MAC or Windows machine to read them, so no real problem. However, be aware that if your are running a RAID configuration in the NAS it becomes more of an issue. RAID 1, assuming no proprietary encoding is used, can usually have one of the drives accessed via another PC. Be very cautious of anything outside of RAID 1 -
here, all other configurations require multiple drives to get a single copy. In the vast majority of SOHO NAS devices available, you could have issues as the firmware that controls the RAID configuration is usually proprietary and, even with the bigger brands, they often don't allow RAID volumes to be transferred to a new NAS rendering all the data inaccessible.
Personally, I take multiple approaches to back up but a simple option, especially with a desk system is to attach a bare-drive enclosure via USB/FW/SATA (they look like this:
http://aluratek.com/media/catalog/p...5d08d6e5fb8d27136e95/a/h/ahdds100f_image3.jpg) and use incremental backup software to ensure consistency and scheduled backups. That way you can rotate a couple of drives easily and know they're up to date.
