CloudMiner -
That's not a short answer subject.
Minimum for RAID-DP is 5 disks, for RAID4 it's 3.
That wouldn't give you very good disk utilization.
Max disk #s depend on the controller platform.
Default RAID group sizes for DP are 14 and 16 for SATA and SAS/FC disks.
In general you want to build your aggrs with equal sized RAID groups and not stray too far from the default RAID group sizes...
I hope this response has been helpful to you.
At your service,
Eugene E. Kashpureff, Sr.
Independent NetApp Consultant http://www.linkedin.com/in/eugenekashpureff
Senior NetApp Instructor, FastLane US http://www.fastlaneus.com/
(P.S. I appreciate 'kudos' on any helpful posts.)