I currently have a 4x500GB RAID 10 set in my Mac Pro. (Two sets of 2x500GB mirrors which are then striped which gives me 1TB of protected data). One of the 500GB drives just failed so instead of just replacing directly, I'd like to do some upgrades. I just came across a cheap 1TB drive which I purchased and I'd like to use in my Mac Pro. Is it possible to replace one of those striped sets with the 1TB drive? Essentially, I'd end up with a mirror of the 1TB drive and a 2x500GB striped set. I know I'll lose the of the performance from the striping, but my concern is if this is simply possible using disk utility. My goal is to eventually replace all the drives so that I end up with 2TB of RAID 10 storage so doing incremental changes isn't a big deal for now. Thanks.