Approaches Towards Energy-Efficiency in the Cloud for Emerging Markets

With the growing importance of the cloud computing paradigm, it is a challenge for cloud providers to keep the operational costs of the data centers in check, especially in the emerging markets, alongside catering to the customers' needs. It becomes essential to increase the operational efficiency of the data centers to be able to maximize VM (Virtual machine) offerings at minimal cost. To that end, energy-efficiency of the servers plays a critical role, as they influence the electrical and the cooling costs which constitute a major part of the total cost involved in the operation of a data center. Power-savings can be achieved at several different levels in a system: processors, memory, devices, and system-wide (involving powering down multiple components of a host all at once). At the processors level, depending on the workload trends, we can exploit technologies like DVFS (Dynamic Voltage and Frequency Scaling) or P-states when the CPU is running, and CPU sleep states (C-states) when the CPU is idle, to save power. Memory standards such as DDR3 have provisions for putting idle memory banks into low-power states. At the devices level, individual devices can be put into low-power states, controlled and co-ordinated by a run-time power management framework in the Operating System. This paper outlines the state-of-the-art in power- management technology on server hardware and describes how these raw features can be abstracted into a set of energy policies. We then explain how these policies or energy-profiles can be used to run a cloud datacener energy efficiently. Further, this paper also highlights some of the challenges involved in running cloud infrastructures in the emerging markets optimally despite some unique energy constraints.