A PROactive Request Distribution (PRORD) Using Web Log Mining in a Cluster-Based Web Server

Widely adopted distributor-based systems forward user requests to a balanced set of waiting servers in complete transparency to the users. The policy employed in forwarding requests from the front-end distributor to the backend servers dominates the overall system performance. The locality-aware request distribution (LARD) scheme improves the system response time by having the requests serviced by the Web servers that contain the data in their caches. In this paper, we propose a proactive request distribution (PRORD) that applies an intelligent proactive-distribution at the front-end and complementary pre-fetching at the back-end server nodes to obtain the data of high relation to the previous requests in their caches. The prefetching scheme fetches the Web pages in advance into the memory based on a confidence value of the Web page, which is predicted by the proactive distribution scheme. Designed to work with the prevailing Web technologies, such as HTTP 1.1, our scheme aims to provide reduced response time to the users. Simulations carried out with traces derived from the log files of real Web servers witness performance boost of 15-45 % compared to the existing distribution policies