> 3) Do I have to start with a set of blank drives? Right now 1 of the > 3 drives has about 200GB of data on it which would not be > easy to backup and get off the drive. >
I'm pretty sure I've seen RAID cards that can do online expansion of their raid volumes. If you decide on one that can do this then get a fourth 250gig disk so you have a 3 disk RAID 5 set, copy all your data onto it then either keep the fourth drive as a spare or combine it into the volume :)