A QoS-Aware Middleware for Fault Tolerant Web Services

Reliability is a key issue of the service-oriented architecture (SOA) which is widely employed in critical domains such as e-commerce and e-government. Redundancy-based fault tolerance strategies are usually employed for building reliable SOA on top of unreliable remote Web services. Based on the idea of user-collaboration, this paper proposes a QoS-aware middleware for fault tolerant Web services. Based on this middleware, service-oriented applications can dynamically adjust their optimal fault tolerance strategy to achieve good service reliability as well as good overall performance. A dynamic fault tolerance replication strategy is designed and evaluated. Experiments are conducted to illustrate the advantage of the proposed middleware as well as the dynamic fault tolerance replication strategy. Comparison of the effectiveness of the proposed dynamic fault tolerance strategy and various traditional fault tolerance strategies are also provided.