A nonblocking quorum consensus protocol for replicated data

A nonblocking quorum protocol for replica control which guarantees one-copy serializability is developed. The effects of a nonblocking protocol are analyzed, and it is shown that the gains can be substantial under certain conditions. It is demonstrated that in order for the protocol to be useful, it must be integrated with a propagation mechanism. It is also shown that the access latency can be reduced significantly in a replicated environment. An interesting aspect of the quorum protocol is that it essentially uses a read quorom/write-quorom approach for concurrency control but uses a read-one/write-all approach for replica control. It is shown that the nonblocking quorom protocol provides the same level of availability and fault tolerance as the quorum protocol proposed by D.K. Gifford (1979)