A market-based architecture for management of geographically dispersed, replicated web servers

Abstract

Many popular Web sites employ a set geographically dispersed, replicated servers to address the issue of overloaded servers and network congestion. Such distributed Web sites require allocation mechanisms to dispatch request in a way such that any desired load distribution can be enforced. Unlike most traditional approaches, we propose a technique which pushes the allocation functionality onto the client. We argue that this approach scales well and may result in increased performance in many cases. Building on theoretical work based on game theory, we show that the usage of individual replicas can be effectively controlled with cost functions even when the clients are noncooperative. We present the design and implementation of WcbSeAl, our prototype system realizing these techniques. WebSeAl does not require any changes to existing client and server code, conforms to HTTP standards, and does not generate any control messages. Experiment results Indicate that WebSeAl improves performance while imposing little overhead.