At risk of labouring the point, but another nice thing about RAID 1+0 is the resync time. Say 4+4 73GB disks, or 4(1+1) since you're into maths today! With RAID 1+0 you get to resync 73GB of data if you lose a single disk and replace it (hot spare or otherwise). With RAID 0+1 in the same scenario you get to twiddle your thumbs whilst performance dives in resyncing 292GB of data. Des