Last December, our colleague Dr. Marina Zapater traveled to Las Vegas, USA, to present her last paper “Dynamic workload and cooling management in High-Efficiency data centers” in the International Green and Sustainable Computing Conference (IGSC) 2015. The work presented is part of our on-going collaboration with the PeacLab group at Boston University, with Prof. Ayse Coskun.
This work is the first one in which we tackle high-efficiency low-PUE 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 the Massachusetts Green HPC Center in Holyoke (MA), 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.