Patent ID: 7243089

Claim:
A processor-implemented method of federating a local file system into a distributed file system while preserving local access to an existing data in the local file system, comprising: adding a federation layer that allows both a local client and a plurality of distributed clients to access the existing data; allowing local applications to access both the existing data in the local file system and data in other parts of the distributed file system; wherein the federation layer establishes a detour between the local applications and the local file system, to provide access to the distributed file system; generating a unique object ID number for each object found in the local file system, as a tuple <I,G> of an mode number of the object found in the local file system and a generation number; wherein the generation number is increased anytime a same mode number is found for a different object; wherein the federation layer contains a database that stores the unique object ID number and that maps a file name and a corresponding unique object ID number; and maintaining a deleted flag in the database for objects that have been deleted, so the occurrence of the same mode number for different objects are recognized.