I currently have two 1 TB Seagates in my Mac Pro (2.8 Ghz 2008), with one being my main drive and the other my Time Machine drive. I am wanting to add two more 1 TB drives of the same model and set up a software RAID 10 across all four drives. Problem is, I need to migrate almost 1 TB of data off the current setup onto the new, but I can't afford an external, especially just for this task. Does anyone know of a way to accomplish this? I initially had the idea of restoring from TM unto the new RAID 1 set, then erasing the two original drives and reconfiguring them into a RAID 1 set, but then I realized I'd have to erase all four disks to stripe the two pairs - is there any way around this?