Locality-Aware Request Distribution with Frequency-based Replication in Web Server Clusters

Abstract

As services of WWW popularize and evolve, the capability of servers is highly concerned for conforming to modern and future requirements. The cluster-based web system is one of the solutions to meet the above requirements. Recently, in this cluster-based web system, content-aware request distribution policies become an important issue to effectively dispatch requests from clients to servers. In this research, we propose a new dispatching policy named LARD/FR which improves from the well-known LARD/R policy. LARD/R policy allows a set of the back-end servers (server set) to serve the same target web object to increase the cache-hit ratio of back-end servers. By using a frequency-based mechanism, LARD/FR achieves higher cache hit rates of servers than LARD/R. We have implemented the proposed distribution policy on our LVS-CAD platform and practical experiments show it outperforms some other content-aware request distribution policies.