Content-aware cooperative caching for cluster-based web servers

Most traditional cooperative caching schemes were developed for network file systems but were not designed for cluster-based web servers with content-based request distribution. Hence, although the schemes are applied to the web servers, their performance is not good due to high disk accesses and large block access latency. This paper proposes and evaluates a new cooperative caching scheme suitable to file systems in web servers. It uses a cache replacement policy, called duplicate first copy replacement, to avoid caching unnecessary data produced during serving requests and to minimize disk accesses. In addition it reduces block access latency required to fetch a file-block in the cooperative cache. A simulation shows that our cooperating caching decreases the disk access ratio by 29%, and reduces block access latency by about 26% when compared to the existing cooperative algorithms. (C) 2003 Elsevier Inc. All rights reserved.