onehunga,
Sleep is highly over rated.
It was a long night at work, and I was just checking PPRuNe before going to bed. (As I am sure you noticed, I missed your reply 15 minutes after my post.)
Here is some info on RAID by Anand Tech. The article was written back in June of 2001 but the info on what RAID is and how is works is well worth the read:
IDE RAID Comparison
With the current reliability rate of Hard Drives, it is an option running Striped Drives without much added chance of data loss.
Take Care,
Richard