Power Reduction Scheme of Fans in a Blade System by Considering the Imbalance of CPU Temperatures

In order to develop a data center power efficiency index, we built a test bed of a data center and measured power components and environmental variables in some detail, including the power consumption and temperature of each node, rack and air conditioning unit, as well as load on the CPU, Disk I/O and the network. In these measurements we found that there was a significant imbalance of CPU temperatures that caused an imbalance in the power consumption of fans. We clarified the relationship between CPU load and fan speed, and showed that scheduling or rearrangement of nodes could reduce the power consumption of fans. We reduced fan power consumption by a maximum of about 350 W by changing the scheduling of five nodes, changing the nodes used from hot nodes to cool nodes.