Dynamic workload and cooling management in high-efficiency data centers

Energy efficiency research in data centers has traditionally focused on raised-floor air-cooled facilities. As rack power density increases, traditional cooling is being replaced by close-coupled systems that provide enhanced airflow and cooling capacity. This work presents a model for close-coupled data centers with free cooling, and explores the power consumption trade-offs in these facilities as outdoor temperature changes throughout the year. Using this model, we propose a technique that jointly allocates workload and controls cooling in a power-efficient way. Our technique is tested with configuration parameters, power traces, and weather data collected from real-life data centers, and application profiles obtained from enterprise servers. Results show that our joint workload allocation and cooling policy provides 5% reduction in overall data center energy consumption, and up to 24% peak power reduction, leading to a 6% decrease in the electricity costs without affecting performance.