There has been some confusion -- FAN has added yet another acronym for storage professionals to contend with, along with backup area networks and other marketing-driven initiatives. FAN means "file area network." It's a marketing term being driven by Brocade.
Fortunately, FAN is an umbrella term, and anyone that thinks from a network-centric viewpoint will probably embrace the file serving/sharing or virtualization and NAS accessorization promoted by a FAN. But, there is some confusion with file virtualization. The two ideas are mutually exclusive, so file virtualization does not require FAN (and vice versa). Still, other vendors are jumping on the FAN bandwagon.
Go back to the beginning of the File Virtualization FAQ Guide.