use RAID to backup the backup?
 

I worry about the precious copy of my precious data. Suppose I have SD! write to a RAID made by Disk Utility? Is this a good idea? At the moment, I make a third copy now and then, but it won't be up to date the day that a disk fails. I know that I could use SD! to back up to two disks, but this powerbook has just one FW800 and one FW400 and I already have a lot of cables on the desk.

Having one spare tire means you can get to a repair shop, but having two spare tires means that you can go on with the vacation.

DGarboczi