In reply to Marwan.

Excellent question. With all of these architectural and design questions, I think I'm going to have to write a more specific, detailed blog on how this is put together. :)

The important thing to remember at this point is that the spine does not process FCoE traffic, which means that there is no Fibre Channel Forwarder (FCF). If there's no FCF, then the N7k does not have to have a storage VDC (nor a license) in the spine. The only thing that will be necessary is for the spine to be able to handle SRC/DST/OXID load-balancing of Fibre Channel traffic, which is how we handle port-channels between switches right now.

Hope that helps. :)