A CDF-based tool for studying temperature in rack-mounted servers

Temperature-aware computing is becoming more important in the design of computer systems as power densities are increasing and the implications of high operating temperatures result in higher failure rates of components and increased demand for cooling capability. Computer architects and system software designers need to understand the thermal consequences of their proposals and develop techniques for lowering operating temperatures to reduce both transient and permanent component failures. Until recently, tools for understanding the temperature ramifications of the designs of the server and the rack have been mainly restricted to the industry for studying packaging and cooling mechanisms and they have been mainly concerned with the static thermal characteristics of computer systems. Recognizing the need for such tools, there has been recent work on modeling temperatures of processors at the microarchitectural level, which can be easily understood and employed by computer architects for processor designs. However, there is a dearth of such tools in the academic/research community for undertaking architectural/systems studies beyond a processor-a server box, rack, or even a machine room. In this paper, we present a detailed three-dimensional Computational Fluid Dynamics-based thermal modeling tool, called ThermoStat, for rack-mounted server systems. We conduct several experiments with this tool to show how different load conditions affect the thermal profile and to also illustrate how this tool can help design dynamic thermal management techniques. We propose reactive and proactive thermal management for rack-mounted server and isothermal workload distribution for rack.