Joseph Cunliffe

US Patent:

6467046, Oct 15, 2002

Filed:

May 6, 1996

Appl. No.:

08/643550

Inventors:

Joseph E. Cunliffe - Colorado Springs CO
Dale R. Passmore - Colorado Springs CO

Assignee:

Sun Microsystems, Inc. - Palo Alto CA

International Classification:

H02H 305

US Classification:

714 6, 714 47, 714 49

Abstract:

A computer implemented system, method and computer program product for automatically distributing copies of a replicated database for a computer system comprising at least first and second host computers. Each of the host computers operatively control at least one associated computer mass storage device controller coupled to commonly accessible computer mass storage devices by at least one storage device bus. The system and method comprises the step of enumerating each of the various host computers of the computer system, each of the computer mass storage device controllers associated with each host computer and each of the computer mass storage devices coupled to the storage device buses coupling the controllers. Copies of the replicated database are then automatically distributed across the computer mass storage devices such that failures of one or more of the computer mass storage device controllers or of one or more of the computer mass storage devices will not interrupt operation of the replicated database in the computer system.

US Patent:

57403481, Apr 14, 1998

Filed:

Jul 1, 1996

Appl. No.:

8/673082

Inventors:

Joseph E. Cunliffe - Colorado Springs CO
Dale R. Passmore - Colorado Springs CO

Assignee:

Sun Microsystems, Inc. - Mountain View CA

International Classification:

G06F 1118

US Classification:

39518204

Abstract:

A system, method and computer program product for ensuring that a replicated computer database does not encounter a "split brain" problem by replicating the database and requiring a replica quorum wherein at least (50% +1) of the replicas are accessible and in agreement. When a replica quorum in not obtainable, but 50% of the copies of the data are in agreement, an external source, or "mediator", is called upon to provide a deciding vote (+1) to ensure that the data can be trusted.