An evaluation of the Amoeba group communication system

The Amoeba group communication system has two unique aspects: (1) it uses a sequencer-based protocol with negative acknowledgements for achieving a total order on all group messages; and (2) users choose the degree of fault tolerance they desire. This paper reports on our design decisions in retrospect, the performance of the Amoeba group system, and our experiences using the system. We conclude that sequencer-based group protocols achieve high performance (comparable to Amoeba's fast remote procedure call implementation), that the scalability of our sequencer-based protocols is limited by message processing time, and that the flexibility and modularity of user-level implementations of protocols is likely to outweigh the potential performance loss.