Found the answer:

Even in FCP world, you will have to set a preferredIP address. The procedure to do this is as follows:

http://now.netapp.com/Knowledgebase/solutionarea.asp?id=kb4350 http://now.netapp.com/Knowledgebase/solutionarea.asp?id=kb4350

By setting a PreferredIP address, you will prevent VIFs from flaking out

Snapdrive MUST have an Ethernet connection to the filer regardless of the SAN implementation. The Snapdrive "Command & Control" traffic will not flow across the SAN. Snapdrive is using ZAPI and CIFS calls to communicate with the filer and that can only travel over a public Ethernet connection.