1. A system comprising: Federated File System (Federated FS), the Federated FS comprising one or more network attached storage (NAS) file servers that stores directory sets that are exclusive to one or more virtual machines (VMs); NAS Virtualization Management system (NAS VMS), which interfaces with a Virtualization Management system; and one or more NAS clients associated with the VMs and optionally enhanced to understand extended semantics for controlling NAS referrals.