You may be correct, but I didn't think this was the case, especially since I read this in the 7.3.2 Network Management Guide:

Balance NFS traffic on network interfaces
You can attach multiple interfaces on your storage system to the same physical network to balance network traffic among different interfaces.
For example, if two Ethernet interfaces on a storage system named toaster are attached to the same network where four NFS clients reside, specify in the /etc/fstab file on client1 and client2 that these clients mount from toaster-0:/home. Specify in the /etc/fstab file on client3 and client4 that these clients mount from toaster-1:/home. This scheme can balance the traffic among interfaces if all clients generate about the same amount of traffic.
Your storage system always responds to an NFS request by sending a reply using the interface over which the request was received.

 

Thoughts?

Romeo