Dynamic Light-Weight Groups

The virtual synchrony model for group communication has proven to be a powerful paradigm for building distributed applications. In applications that use a large number of groups, signi cant performance gains can be attained if these groups share the resources required to provide virtual synchrony. A service that maps user groups onto instances of a virtually synchronous implementation is called a LightWeight Group Service. This paper discusses the Light-Weight Group protocols in dynamic environments, where mappings cannot be de ned a priori and may change over time. We show that it is possible to establish mappings that promote sharing and, at the same time, minimize interference. These mappings can be established in an automated manner, using heuristics applied locally at each node. Experiments using an implementation in the Horus system show that signi cant performance improvements can be achieved with this approach. Selected section of this report were published in the Proceedings of the 17th IEEE International Conference on Distributed Computing Systems, Baltimore, Maryland, USA, May, 1997. This work was partially supported by the CEC, through ESPRIT/ BRA Working Group 26 (GODC) and the ARPA/ONR grant N00014-92-J-1866.