Cooperative Caching of Dynamic Content on a Distributed Web Server

In this paper we propose a new method for improving the average response time of Web servers by cooperatively caching the results of requests for dynamic content. The work is motivated by our recent study of access logs from the Alexandria Digital Library server at UCSB, which demonstrates that approximately a 30 percent decrease in average response time could be achieved by caching dynamically generated content. We have developed a distributed Web server called Swala, in which the nodes cooperatively cache the results of CGI requests, and the cache meta-data is stored in a replicated global cache directory. Our experiments show that the single-node performance of Swala without caching is comparable to the Netscape Enterprise server, that considerable speedups are obtained using caching, and that the cache hit ratio is substantially higher with cooperative cache than with stand-alone cache.