Using reconfiguration for efficient management of replicated data

Replicated data management protocols have been proposed that exploit a logically structured set of copies. These protocols have the advantage that they provide limited fault-tolerance at low communication cost. The proposed protocols can be viewed as analogues of the read-one write-all protocol in the context of logical structures. In this paper, we start by generalizing these protocols in two ways for logical structures. First, the quorum based approach is applied to develop protocols that use structured read and write quorums, thus attaining a high degree of data availability for both read and write operations. Next, the reconfiguration or views approach is developed for these structures resulting in protocols that attain high degrees of availability at significantly low communication cost for read operations. In this sense, the proposed protocols have the advantages of the read-one write-all protocol for low cost read operations as well as the majority quorum protocol for high data availability. Finally, we generalize the reconfiguration approach to allow for the dynamic reconfiguration of the database system from one replica management protocol to another. This allows database systems to adapt to an evolving and dynamic application environment.