Hi Again, Thanks everyone for your advice ... let me see if I can get this straight : -) I'll assume I'm using 4 drives, 3 x 4Gb, 1 x 9Gb ... 1. I can create a software raid across all three drives if I create partitions (type 0xFD I believe) of equal size on all four disks. Using a stripe RAID (Raid 0?) that will give me a total partition of 16Gb. 2. That will leave me around 5Gb on the 9Gb drive whih I could (should?) separate into three partitions: boot, swap & spare: In other words (I don't know the cylinder numbers): ID0 (9Gb, /dev/sda): /dev/sda1: Boot (512Mb) /dev/sda2: Raid (4Gb) /dev/sda3: Spare (4Gb) /dev/sda5: Swap (512Mb) ID1 (4Gb, /dev/sdb): /dev/sdb1: Raid (4Gb) ID2 (4Gb, /dev/sdc): /dev/sdc1: Raid (4Gb) ID3 (4Gb, /dev/sdd): /dev/sdd1: Raid (4Gb) Thanks again for your help :-) James James C. Rocks Equant Archway House Canary Wharf London E14 9SZ