keiichiroy, if you worry about the breakdown of the hard disk, I think that it is the best to use the RAID function.
But this time, your motherboard must support RAID function, and it need some skills about harddisk.
I'm regrettable that I can't help you, because I didn't use RAID...
See Wikipedia for more information...
http://en.wikipedia.org/wiki/Redundant_array_of_independent_disks
22-Feb-2006