I will only do it for the striping part, hence the RAID 0 for performance. If I'm running a machine that have critical info for business purpose or life/death issue, then I will most definitely run the RAID 0+1. RAID 0 sees the two hard drives as one so you're really not getting any redundancy there. If one drive fails, the whole thing is screwed up. WIth RAID 0+1, if one fails, I believe the other one still functions but the striping part would be lost. I think...