The CÆSARA architecture for power and thermal-aware placement of virtual machines

Energy consumption of data centers increased continously during the last decades. As current techniques for improving their energy efficiency are usually limited to one type of data center components, it is difficult to employ them for a holistic optimization which may utilize synergies between all components. This paper shortly presents architecture and working principles of the novel energy management system CÆSARA that applies a comprehensive view for evaluating an energy-efficient virtual machine placement in current virtualization environments for minimizing the number of running energy-consuming physical machines. In contrast to existing solutions, our placement algorithm does not only aggregate load to a minimum number of servers - it also discovers which servers in conjunction with their infrastructure act as most energy-efficient migration targets. Thus, the CÆSARA architecture unifies two worlds which are usually separated when finding an energy-efficient configuration: the inner computer world which can be characterized by load values and the infrastructure world which is characterized by physical parameters. This paper presents the architecture of CÆSARA, defines properties for an energy-efficient virtual machine placement algorithm, and sketches how the integration of infrastructural energy consumption can be employed by using a thermodynamic approach. Exemplarily, this is realized by the example of server cooling equipment.