Issue No. 11 - November (2007 vol. 18)
Modern web-based application infrastructures are based on clustered, multi-tiered architectures, where request distribution occurs in two sequential stages: over a cluster of web servers, and over a cluster of application servers. Much work has focused on strategies for distributing requests across a web server cluster in order to improve the overall throughput across the cluster. The strategies applied at the application layer are the same as those at the web server layer, because itis assumed that they transfer directly.In this paper, we argue that the problem of distributing requests across an application server cluster is fundamentally different from the web server request distribution problem, due to core differences in request processing in web and application servers. We devise an approach for distributing requests across a cluster of application servers such that overall system throughput is enhanced, and load across the application servers is balanced.
[H-3-4-b] Distributed systems, [H-3-5-e]Web-based services, [J-8-a] Client/server and multitier systems, [J-8-e] Electronic commerce, [J-8-l] Middleware/business logic
D. VanderMeer, K. Ramamritham, A. Datta, K. Dutta and H. Thomas, "ReDAL: An Efficient and Practical Request Distribution Technique for Application Server Clusters," in IEEE Transactions on Parallel & Distributed Systems, vol. 18, no. , pp. 1516-1528, 2007.