An architecture and system are described that provide a unified file access service within in a managed computing environment composed of diverse networks, computing devices, and storage devices. The service provides mechanisms for remotely accessing the file systems of any managed computer or disk snapshot, independently of the computer's current state (powered on, suspended or powered off), its location within the environment, its hardware type (virtual vs. physical), its operating system type, and its file system formats. The system isolates centralized FPAs from the details of clients, proxies and storage elements by providing a service that decomposes offloaded file system access into two steps. A FPA or a requester acting on behalf of the FPA first expresses the disk set or the computer containing the file systems it wishes to access, along with requirements and preferences about the access method. The service figures out an efficient data path satisfying the FPA's needs, and then automatically configures a set of storage and computing resources to provide the data path. The service then replies with information about the resources and instructions for using them. The FPA then accesses the requested file systems using the returned information.