p‐Jigsaw: a cluster‐based Web server with cooperative caching support
Ge Chen, Cho‐Li Wang, Francis C. M. Lau · Concurrency and Computation Practice and Experience · 2003
Abstract Clustering provides a viable approach to building scalable Web systems with increased computing power and abundant storage space for data and contents. In this paper, we present a pure‐Java‐based parallel Web server system, p‐Jigsaw, which operates on a cluster and uses the technique of cooperative caching to achieve high performance. We introduce the design of an in‐memory cache layer, called Global Object Space (GOS), for dynamic caching of frequently requested Web objects. The GOS provides a unified view of cluster‐wide memory resources for achieving location‐transparent Web object accesses. The GOS relies on cooperative caching to minimize disk accesses. A requested Web object can be fetched from a server node's local cache or a peer node's local cache, with the disk serving only as the last resort. A prototype system based on the W3C Jigsaw server has been implemented on a 16‐node PC cluster. Three cluster‐aware cache replacement algorithms were tested and evaluated. The benchmark results show good speedups with a real‐life access log, proving that cooperative caching can have significant positive impacts on the performance of cluster‐based parallel Web servers. Copyright © 2003 John Wiley & Sons, Ltd.