Patent ID: 7840618

Claim:
In a wide area network having a central file manager and proxy nodes with the central file manager storing files of system data and metadata and the proxy nodes being assigned as one of a home node and a redirector node, the central file manager assigning home nodes ownership of respective ones of the files and the redirector nodes being proxy nodes that are not home nodes, a method for assigning and selecting the proxy nodes over the wide area network comprising the steps of: partitioning a file system's namespace tree into closely related sets of the files; assigning the sets of files to proxy nodes as home nodes such that a request from a client behind the proxy nodes is satisfied by a local said proxy node with high probability, said assigning creating a lookup table, with a limited size, of the files and their respective home nodes by: a) allocating each directory node of at least a subset of the namespace tree to a respective proxy node having the lowest access cost among the proxy nodes for the respective directory node, wherein the access cost is dependent on an estimate of a number of accesses of each proxy node on the respective directory node within a next time interval and on latencies between the proxy node allocated to the respective directory node and each other proxy node, b) weighting each allocation with a weight cost that is based on the corresponding access cost of the respectively allocated proxy node, and c) selecting proxy nodes for insertion into said lookup table for corresponding directory nodes allocated to the proxy nodes such that proxy nodes having lowest weight costs are ensured placement in said lookup table and an directory nodes that are not included in said lookup table when filled are assigned the proxy node of a corresponding, assigned parent directory node; and updating the lookup table each time it is modified by successive assigning steps.