The Storage Subsystem Technical FAQ from Jay White on the Partner Field Portal should give you the answer. The latest is there : https://fieldportal.netapp.com/viewcontent.asp?qv=1&docid=9866 (on page 7)
In order to get the best performance (usually disk bound) I tend to go the Active/Passive way so :
Controller 1 (RAID-DP):
o Number of aggregates = 1
o RAID group size = 8
o Number of data drives = 6
o Number of parity drives = 2
o Number of hot spares = 1
Controller 2 (RAID-DP):
o Number of aggregates = 1
o RAID group size = 3
o Number of data drives = 1
o Number of parity drives = 2
o Number of hot spares = 0* (raid.min_spare_count can be set to 0 to avoid warning messages.)
That should give you an aggregate of 1434.27 GiB with a Snap Reserve at 0% (minus the root volume of 133 GiB with Ontap 8.0 + Snap Reserve)
