An easy solution for me, not being an IT expert, was to use a Drobo. Good thing with this is it automatically backs up files between the hard drives installed in it. Does this all by itself, no input needed from the user, other than to monitor how much capacity is being used. Drives can be hot swapped with no loss of data, though it can take a while for the new HD to be intergrated, depending on how much data is stored. Mine has been on 24/7 for the past three or four years with no issues. I recently swapped the four original 500GB drives for 3tb WD reds.

I still use separate USB drives as a back up though..