Object Replication Using Version Vector - 05/22/2009

Jie Meng

Distributed systems are composed of objects supporting abstract methods. In order to increase the reliability, availability, and performance, objects are replicated in the system. In this talk, we will describe a version vector to maintain the mutual consistency of the replicas. We will introduce an object-based locking (OBL) protocol to lock replicas of objects by extending the quorum-based protocol for read and write to abstract methods. In OBL protocol, subsets of the replicas locked by the methods do not intersect unless two methods conflict. Methods not computed on a replica A but computed on another replica are computed on A when a method conflicting with the methods are issued to A. The version vector is used to in the OBL protocol to identify what methods are computed on a replica. Using the OBL protocol, fewer number of replicas are locked than the traditional quorum-based protocol.