The design and implementation of an active replication scheme for distributing services in a cluster of workstations

Replication is the key to providing high availability, fault tolerance, and enhanced performance in a cluster of workstations (COWs). However, building such a system remains as a difficult and challenging task, mainly due to the difficulty of maintaining data consistency among replicas and the lack of easy and efficient tools supporting the development procedure. In this paper we propose an active replication scheme in which data consistency can be maintained. Based on the active replication scheme, we present an object-oriented design pattern and a constructing tool to simplify the design and implementation of service replications in COWs.

A reactive system architecture for building fault-tolerant distributed applications

Most fault-tolerant application programs cannot cope with constant changes in their environments and user requirements because they embed policies and mechanisms together so that if the policies or mechanisms are  changed the whole programs have to be changed as well. This paper presents a reactive system approach to overcoming this limitation. The reactive system concepts are an attractive paradigm for system design, development and maintenance because they separate policies from mechanisms. In the paper we propose a generic reactive system architecture and use group communication primitives to model it. We then implement it as a generic package which can be applied in any distributed applications. The system performance shows that it can be used in a distributed environment effectively.