Patent 05612865 - Dynamic hashing method for optimal distribution of locks within a clustered system > Summary

Patent No. US 05612865

Published on Mar 18, 1997

Application No. 8/456435

Filed on Jun 1, 1995

Priority Date -

Dasgupta, Ranjan - Naperville, IL (25)

A method for redistributing the mastership of system resources among the processing nodes within the clustered computer system following a change in the system configuration, such as the failure of a processing node or the return to service of a failed processing node. The method includes the steps of: maintaining a set of hash buckets within each processing node; assigning each one of the resources to one of the hash buckets; and assigning a hash vector, determined through utilization of an N-way recursive algorithm, to each one of the hash buckets, each one of the hash vectors identifying the processing nodes within the clustered computer system in a predetermined sequence unique to the one of the hash buckets. Mastership of any system resource resides with the first processing node identified by the hash vector assigned to the hash bucket to which the system resource is assigned. Following the failure of a processing node, the method reassigns mastership of the system resources assigned to the set of hash buckets associated with a failed processing node the next processing node having an active state identified by the hash vector assigned to the set of hash buckets associated with the failed processing node. Mastership of the resources initially assigned to the set of hash buckets associated with the failed node is reassigned to the failed node upon return of the failed node to an active state.