williewonka
... perhaps what you should invest in is a USB or NAS drive that supports dual drive RAID mirroring. If one drive fails in the unit you simply replace it and the RAID software takes care of copying the data from the other disk in the background. You can also listen to the music while this is going on.RAID is a useful protocol, but it is not intended to serve as a backup. RAID can't protect against human error, malware or viruses, or something like a deadly power spike.
RAID requires a hard drive specifically for data servers ...That is mistaken. You can easily setup RAID using pedestrian hard drives - at least on a PC. (I'm not sure about Mac.)
You should also keep an offsite backup ...Agreed!