Service replication in Grids: Ensuring consistency in a dynamic, failure-prone environment

A major challenge in a service-oriented environment as a Grid is fault tolerance. The more resources and services involved, the more complicated and error-prone becomes the system. Migol (Luckow and Schnor, 2008) is a Grid middleware, which addresses the fault tolerance of Grid applications and services. Migol´s core component is its registry service called application information service (AIS). To achieve fault tolerance and high availability the AIS is replicated on different sites. Since a registry is a stateful Web service, the replication of the AIS is no trivial task. In this paper, we present our concept for active replication of Grid services. Migol´s Replication Service uses a token-based algorithm and certificate-based security to provide secure group communication. Further, we show in different experiments that active replication in a real Grid environment is feasible.