Efficient Algorithms to Implement Unreliable Failure Detectors in Partially Synchronous Systems

Unreliable failure detectors, proposed by Chandra and Toueg [2], are mechanisms that provide information about process failures. In [2], eight classes of failure detectors were defined, depending on how accurate this information is, and an algorithm implementing a failure detector of one of these classes in a partially synchronous system was presented. This algorithm is based on all-to-all communication, and periodically exchanges a number of messages that is quadratic on the number of processes. To our knowledge, no other algorithm implementing these classes of unreliable failure detectors has been proposed. In this paper, we present a family of distributed algorithms that implement four classes of unreliable failure detectors in partially synchronous systems. Our algorithms are based on a logical ring arrangement of the processes, which defines the monitoring and failure information propagation pattern. The resulting algorithms periodically exchange at most a linear number of messages.