A dynamic probe strategy for quorum systems

A quorum system is a collection of sets called quorums. Any two quorums in a quorum system must have at least one element in common. Quorum systems can be used for many different applications in a distributed system. A quorum system is available, if all elements in at least one quorum ore operational. The elements are probed to determine if they are available. A probe strategy is used to determine the order in which the elements are probed. This paper studies the average case probe complexity, which is defined as the expected number of probes required to determine if a given quorum system is available. Then, two new probe strategies are presented and analyzed. The first strategy is a generalizations of the alternating color strategy, and the second strategy is based on a measure of the relative importance of each element in the system.