Improving the cooling efficiency of servers has become an essential requirement in data centers today as the power used to cool the servers has become an increasingly large component of the total power usage. Unfortunately, most previous approaches have individually focused on reducing either the server power or the power used by the fans to cool the servers. This paper presents Zephyr, a systems approach to managing fan power that combines conventional server power optimizations with fan power management to optimize overall energy efficiency. By combining distributed system design with concepts from heat transfer theory, Zephyr can reduce cooling power by up to 21% when compared to a feedback-based controller and up to 30% when combined with cooling-aware workload migration policies. Overall, the combined Zephyr system can reduce total system power by up to 29% without impacting application performance.
Designing platform-based system power management on a smart tablet appliance
