I am looking to set up a raid 5 array with 4-8 SSD's and would like a mirrored backup of that system as well (almost like a RAID 51) where the single drive would be a mirror, but obviously i wouldn't have a HDD in a RAID with SSD's. What is the best software utility that will allow me to use that 2TB drive to rebuild the array? is that possible and economically plausible?