A unified framework for load distribution and fault-tolerance of application servers

Abstract

This paper proposes a novel replication architecture for stateful application servers that offers an integrated solution for fault-tolerance and load-distribution. Each application server replica is able to execute client requests and at the same time serves as backup for other replicas. We propose an effective load balancing mechanism that is only load-aware if a server is close to become overloaded. Furthermore, we present transparent reconfiguration algorithms that guarantee that each replica has the same number of backups in a dynamic environment where replicas can join or leave at any time. Our evaluation shows that our approach scales and distributes load across all servers even in heterogeneous environments while keeping the overhead for fault-tolerance and load-balancing small. © 2009 Springer.