Blowing agents

Abstract

Data centers play an important role in modern information technology (IT) infrastructures. A data center is a home to the computational power, storage, and applications necessary to support an enterprise. Data centers process billions of Internet transactions every day. Nowadays, data centers are the beating hearts of the companies they serve. Large data centers with thousands of servers have been deployed by renowned information and communications technology organizations, like IBM, Microsoft, Amazon, Yahoo, eBay, and Google, to provide cloud computing services. The phenomenal increase in the size and number of data centers and the resultant increase in operational cost has stimulated research in various domains of data centers, such as energy efficiency, resource management, networking, and security.Presented are data centers from a cyber-physical system (CPS) perspective. Current methods for controlling IT and cooling technology (CT) in data centers are classified according to the degree to which they take into account both cyber and physical considerations. To evaluate the potential impact of coordinated CPS strategies at the data center level, we introduce a control-oriented model that represents the data center as two coupled networks: a computational network representing the cyber dynamics and a thermal network representing the physical dynamics. These networks are coupled through the influence of the IT on both networks: servers affect both the quality of service (QoS) delivered by the computational network and the generation of heat in the thermal network. Using this model, three control strategies are evaluated with respect to their energy efficiency and computational performance: a baseline strategy that ignores CPS considerations, an uncoordinated strategy that manages IT and CT independently, and a coordinated strategy that manages IT and CT together to achieve the optimal performance with respect to both QoS and energy efficiency. Simulation results show that the benefits that can be realized from coordinating the control of IT and CT depend on the distribution and heterogeneity of the computational and cooling resources throughout the data center. A new cyber-physical index (CPI) is introduced as a measure of this combined distribution of cyber and physical effects in a given data center. We illustrate how the CPI indicates the potential impact of using coordinated CPS control strategies.