Hi all, I recently bought two identical 3TB Seagate USB drives. I have them connected to my Mac Mini and I want to set them up on RAID mirroring for my iTunes library. This is solely for the purposes of protection against a failed disk--I know the caveats regarding mirroring vs backup. However every time I try to create the array in Disk Utility, I get "POSIX reports: the operation couldn't be completed. Operation not permitted." Any ideas, or at least advice where I can get more diagnostic information? Thanks!