RAID 0 – striping – stores data accross several disks, (100 GB drive + 100 GB drive becomes a 200 GB appearing as 1 hard drive icon) improves speed when writing to the drives because it writes to both drives at the same time.
RAID 1 – mirroring — uses the drive to be a redundant copy of the information, provides a back-up if one drive fails.
Disk Utility does not support any other software RAID schemes. However, the XServe RAID rack mountable drive bay delivers additional hardware RAID options.