most SAS users want this to be a redundant file system to ensure the availability of the SAS data. RAID10 in general will give the best redundancy and performance (full mirror plus parity), but the mirror requires you to have more spindles to support the same file space. Please make sure that you mirror the disks before you stripe them for reliability. Most storage administrators employ RAID5 to avoid the cost of extra disks, but keeping the redundancy that parity offers.