Backup Storage for Home (Storage PC Build)

12computers12

Honorable
Jan 19, 2013
3
0
10,510
For a long while I have used two external hard drives to store all my photos and other important data. To make sure I never lost data I had been copying the contents to both of them. However I am finding this increasingly difficult and ending up with only one copy of some of my data. I was thinking that maybe I could set up a old PC I had (Pentium, 4gb Ram.)

(Online storage is not an option)
My plan is to install Ubuntu on a small 120gb hard drive I have, then have two more hard drives set up in RAID 1. (Would this be possible, never used RAID before?) I would then use my external hard drive to copy important stuff off my devices and back it up on this system, and this computer would only be switched on when needed.

It would admittedly be nice to have is set up as a server but my main concerns are; I won't be using server grade HDDs, I worry about security I would only want it accessible by computers in my LAN(Some data sensitive), and I know little about networking.

Finally the motherboard on the spare computer also does not have any USB 3 ports, so I would need a PCI adapter, but would I find drivers for it, if I had Ubuntu?
Please feel free to offer suggestions if my idea seems crazy!
Thanks!