Please see the "SAN Configuration Guide" which is part of the standard documentation set for each Data ONTAP release. It is In it you will find a section titled "Configuration limits for FC, FCoE, and iSCSI configurations" which includes a variety of SAN related maximums per hardware type for that specific Data ONTAP release. Here is a link to the aforementioned page for the 8.1.2 release to get you started.
Hope that helps.
Storage Architect, NetApp EMEA