Using Virtual Synchrony to Develop Efficient Fault TolerantDistributed Shared Memories

Abstract

This paper shows how to define consistency conditions for distributed shared memories in virtually synchronous environments. Such definitions allow to develop fault tolerant implementations of distributed shared memories, in which during normal execution, operations can be performed very efficiently, and only those operations which take place during a configuration change must be delayed. Three well known consistency conditions, namely, linearizability, sequential consistency, and causal memory, are redefined for virtually synchronous environments. It is then shown how to provide efficient fault tolerant implementations for these definitions.