Potentially malfunctioning components in large distributed shared memory systems require highly available services that can be configured according to expected failure rates in the environment. Although several coherence protocols have been developed for DSM systems,1 few address configurability and fault tolerance. To make complex computer systems more robust and fault tolerant, data must be replicated for high availability, and the level of replication must be configurable to control overhead costs. Using an application suite, the authors test several distributed shared memory coherence protocols under different workloads and analyze the operation costs, fault tolerance, and configurability of each.