On improving performance and conserving power in cluster-based Web servers

With the growing use of cluster systems in Web servers, file distribution and database transactions, power conservation and efficiency have been identified as critical issues in the design of cluster systems. Widely adopted, distributor-based systems forward client requests to a balanced set of backend servers in complete transparency to the clients. In this paper, we use power and locality-based request distribution at the distributor to provide optimum power conservation, while maintaining the required QoS of the system. The distribution scheme uses a simple memory management technique using pinned memory on the backend servers and proactive distribution, with the aid of data organization of the Web site, to improve the locality of the files. A simple on-off based power management scheme is applied to conserve power. Our scheme provides reduced response time to the clients and improved power conservation at the backend server cluster without compromising performance. Simulations involving real-time Web traces and latest Web technologies witness performance boost of 15-23% and power conservation of 15-48% over the existing policies.