UPS-Aware Workload Placement in Enterprise Data Centers

Energy efficiency has become a very important concern for enterprise data centers due to the significant cost on electricity. To improve the energy efficiency of data centers, researchers and practitioners have proposed enormous work to reduce the energy consumption of data centers. Most of previous work focus on reducing the energy consumption of IT equipment; however, the power losses caused by uninterruptible power supply (UPS) is not considered, which could account for 15% of the total energy cost of a data center. Recent trend shows that rack level UPSes are getting popular. In this work, we focus on power minimization for both IT equipment and power losses of rack level UPS in an enterprise data center. We propose a rack level power model that builds a direct relationship between IT workload and its power dissipation. Based on this rack level power model, we formulate a mathematical formula for the workload placement optimization problem. The experimental results show that the rack level power model precisely matches the measured power, and the error rate is within ±2.5%. The simulation also indicates up to 5.2% power saving compared to uniform workload allocation, which means $1.425 millions/yr energy cost savings for a 76 megawatts data center with PUE 1.7.