Flexible Heterogeneous Strict Quorum-Based Dynamic Data Replication Schemes

Modern distributed systems are highly dynamic in nature with processes arriving and departing deliberately. Traditional strict quorum-based data replication schemes are either static or limited in their dynamics by a fixed, a priori defined upper bound on the number of processes manageable at run-time. Moreover, they are homogeneous meaning that a single scheme-inherent strategy for building quorum systems is used at every stage of the dynamics. In this paper, we present a novel unifying method for the specification of heterogeneous dynamic strict quorum-based data replication schemes which includes homogeneous schemes as a special case. The method allows to adapt to an unbounded number of processes at run-time and provides new means to flexibly trade-off important quality measures like, e.g., operation availability and costs by beneficially exploiting heterogeneity.