Building Energy-Efficient Web Servers Using Low Power Devices: Opportunities and Challenges

Power consumption has become one major challenge in designing highperformance servers. Recently, some researchers postulate that better energy efficiency can be achieved by using low power devices originally designed for mobile embedded systems. In this report, we validate this hypothesis by measuring the power and the performance of web servers on system level. We consider the power and the energy consumption of processors, memory, and hard disk drives. Our data indicate that, compared with a Pentium4-based web server, a XScale-based computer can achieve more than 1.7 times higher energy efficiency (web pages per Joule) while its throughput (web pages per second) is less than 20%. Our comparison includes both static and dynamic web pages with different sizes. We also indicate some challenges to design an energy-efficient high-performance web server by using this approach.