CloudESE: Energy efficiency model for cloud computing environments

In this paper, we propose two energy models based on a statistical analysis of a server´s operational behavior in order to minimize the energy consumption in data centers at cloud computing providers. Based on these models, the Energy Savings Engine (ESE) in the cloud provider decides either to migrate the virtual machines (VMs) from a lightly-loaded server and then turn it off or put it in a sleep mode, or to keep the current server running and ready to receive any new load requests. The main difference between the two models is the energy and time required to put the server in operational mode from a sleep mode or from an off state. Therefore, the decision is a tradeoff between the energy savings and the required performance according to the SLA between the client and the cloud provider. We show results based on actual power measurements taken at the server´s AC input, to determine the energy consumed in the idle state, the sleep state, the off state and in the case of switching between any two of these states. In addition, we measured the power consumed by the source and the destination servers during the migration of a VM.