Abstract: When receiving a client data access request directed to a first data container serviced by a first federation member, data of the first requested data container may be used to resolve a context identifier and identify a volume location database (VLDB) associated with a second federation member servicing a second data container. A look up request may then be sent to the VLDB to identify one or more locations of the second data container. The client's original data access request illustratively may then be responded to with the identified one or more locations of the second data container.

Abstract: A system and method for referent-controlled location resolution of resources in a federated distributed system. When a client requests access to a data container from a storage system that is a member of a first federation, the storage system determines whether the requested data of the data container is locally stored. If the requested data is not locally stored, i.e., a junction exists in the local volume referencing a second volume serviced by a second federation member, the first federation member identifies the appropriate context identifier (CID) associated with the junction. The junction illustratively contains a remote volume locator and an object identifier. The CID identifies a VLDB that contains location information related to the desired data container. The first federation member resolves the CID to an appropriate VLDB service and sends a lookup request to the identified VLDB associated with the second federation member.

Abstract: Location-independent references include a live reference containing a location of a remote object and a universally unique identifier (UUID) which provides a unique global reference to that remote object. If a method call to the remote object using the live reference fails, the UUID is used to obtain a new reference to the remote object and the new reference is then used to make another method call. A new reference can be obtained from an identifier directory that contains a mapping between UUIDs and location-independent references. When a remote object is first created, or when a remote object is moved from one location to another, the remote object registers with any and all such directories that it can find in its environment. These registrations are leased; that is, if they are not occasionally refreshed by the remote object which registered them, they are dropped from the directory.

Abstract: In a data storage system, content-containing objects to be stored are added to a storage hierarchy that is based on content relationships. The content of each stored object is encrypted and a stub is associated with that object. For each stored object other than a root object, the stub comprises a function of a decryption key for the content of that object and the stubs of all of the ancestors of that object. The stubs can be used to calculate a new stub for a data object to be inserted into the storage hierarchy and to generate a decryption key for an existing object. Since these latter calculations for an object involve the stubs of all ancestors of that object, deleting a stub for an object securely deletes that object and all its descendants. An object can be moved by recalculating its stub.

Abstract: An extensible fingerprint comprised of an ordered list of fingerprints generated by applying each of a plurality of distinct fingerprinting functions to the content of a data item. The extensible fingerprint can be extended by using a new fingerprinting function to compute a new fingerprint and adding the new fingerprint to the list so that the old extensible fingerprint of a data item is used as a prefix of the new extensible fingerprint for that data item. Thus, the fingerprint can be incrementally extended over time. A content-addressed storage system uses extensible fingerprints as addresses and can also change over time.