I have four two terabyte drives in my server, with one of those drives
running a compressed backup of what is on the other three drives.
I think I about two terabytes of data on the server which consists of
backups of the three computers in the house, folders for archives, about
750 GB of movies, et cetera. I do nightly backups of my desktop, plus
weekly backups of my wife's computer and my laptop. I also run an apple
Time Machine backup of my desktop computer to a separate external one
terabyte drive.
Why not RAID them? With 4 drives you can set up a fairly high
efficiency array and have a soft failure of any single drive. With
some controllers you don't even need to bring the system down to swap
out the bad drive. The whole thing is invisible to the OS.
SATA hardware itself is hot swap capable.
He can't afford to pay his taxes. Do you really think he can afford a
$1500 Raid controller?