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2018 ACM/IEEE 45th Annual International Symposium on Computer Architecture (ISCA) (2018)
Los Angeles, CA, USA
June 1, 2018 to June 6, 2018
ISSN: 2575-713X
ISBN: 978-1-5386-5985-4
pp: 15-28
ABSTRACT
As the power density and power consumption of large scale datacenters continue to grow, the challenges of removing heat from these datacenters and keeping them cool is an increasingly urgent and costly. With the largest datacenters now exceeding over 200 MW of power, the cooling systems that prevent overheating cost on the order of tens of millions of dollars. Prior work proposed to deploy phase change materials (PCM) and use Thermal Time Shifting (TTS) to reshape the thermal load of a datacenter by storing heat during peak hours of high utilization and releasing it during off hours when utilization is low, enabling a smaller cooling system to handle the same peak load. The peak cooling load reduction enabled by TTS is greatly beneficial, however TTS is a passive system that cannot handle many workload mixtures or adapt to changing load or environmental characteristics. In this work we propose VMT, a thermal aware job placement technique that adds an active, tunable component to enable greater control over datacenter thermal output. We propose two different job placement algorithms for VMT and perform a scale out study of VMT in a simulated server cluster. We provide analysis of the use cases and trade-offs of each algorithm, and show that VMT reduces peak cooling load by up to 12.8% to provide over two million dollars in cost savings when a smaller cooling system is installed, or allows for over 7,000 additional servers to be added in scenarios where TTS is ineffective.
INDEX TERMS
computer centres, cooling, melting, phase change materials, power aware computing, power consumption, scheduling
CITATION

M. Skach, M. Arora, D. Tullsen, L. Tang and J. Mars, "Virtual Melting Temperature: Managing Server Load to Minimize Cooling Overhead with Phase Change Materials," 2018 ACM/IEEE 45th Annual International Symposium on Computer Architecture (ISCA), Los Angeles, CA, USA, 2018, pp. 15-28.
doi:10.1109/ISCA.2018.00013
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