Under 10.8.4 with a 2012 Mac Pro, I can not setup a mirror RAID using the Apple Disc Utility and Seagate 3TB Drives. There is no problem using 2TB Drives for the mirror RAID but when the 3TB Drives are installed the disc utility does not have a RAID option however the drives have mounted and formatted. The partition option is also strange in that only one or two partitions are permitted. Discussions with Apple suggested not using 3TB Dries for RAID appliations. Has anyone encountered a similar probem?