Data centers can go green by saving electricity in two major areas: computing and cooling. Servers in data centers require a constant supply of cold air from on-site cooling mechanisms for reliability. An increased computational load makes servers dissipate more power as heat and eventually amplifies the cooling load. In thermal-aware scheduling, computations are scheduled with the objective of reducing the data-center-wide thermal gradient, hotspots, and cooling magnitude. Complemented by heat modeling and thermal-aware monitoring and profiling, this scheduling is energy efficient and economical. A survey is presented henceforth of thermal-ware scheduling and associated techniques for green data centers.

Thermal-Aware Scheduling in Green Data Centers

The relationship among CPU utilization, temperature, and thermal power for waste heat utilization

An electrical simulation model for photovoltaic cells, modules, and arrays has been developed that will be useful to a wide range of analysts in the photovoltaic industry. The Microsoft{reg_sign} Windows{trademark} based program can be used to analyze individual cells, to analyze the effects of cell mismatch or reverse bias(`hot spot`) heating in modules and to analyze the performance of large arrays of modules including bypass and blocking diodes. User defined statistical variance can be applied to the fundamental parameters used to simulate the cells and diodes. The model is most appropriate for cells that can be accurately modeled using a two-diode equivalent circuit. This paper describes the simulation program and illustrates its versatility with examples.

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PVSIM{copyright}: A simulation program for photovoltaic cells, modules, and arrays

Reducing costs plays a crucial role in building and operating data centers. Internet service providers such as Facebook and Google spend billions of dollars on capacity expansion and operations of their global data centers. Traditionally, capacity planning for data centers is done separately from operational management, which incurs inefficiency. In fact, operational management has significant impacts on capacity planning. Motivated by this gap, we propose a framework that jointly optimizes both capacity planning and operational management for sustainable data centers and data centers participating in demand response programs. Numerical results based on real-world cases highlight that the proposed framework remarkably reduces up to 50% of total expenditures and 75% of greenhouse gas emissions compared to conventional methods. Additionally, our results show that participations in various demand response programs result in vastly different capacity planning decisions and lead to emission reductions of up to 60%.

Joint capacity planning and operational management for sustainable data centers and demand response

Mechanisms are provided for determining the physical location of a physical asset in a physical area A plurality of physical assets are controlled to cause each physical asset to output a visual output pattern on visual output elements of the physical asset An image of a target physical asset is captured that has the current state of the visual output elements An identification of the target physical asset is determined based on the current state of the visual output elements A physical location of the target physical asset is determined based on a physical location of the image capture device when the image was captured Location data identifying the determined physical location of the target physical asset is stored in an asset database in association with configuration information for the physical asset

Information Technology Asset Location Using Visual Detectors

The energy consumption of data centers (DCs) has dramatically increased in recent years, primarily due to the massive computing demands driven by communications, banking, online retail, and entertainment services In today's data centers, the cooling and infrastructure operations require almost the same energy as the IT operations The large energy consumption in data centers prompted government agencies, industries, professional organizations, and academic institutions to investigate sustainable growth paths We discuss such scenarios based on current trends and projections and propose the required innovations to achieve a 10 fold increase in “performance per Watt” of IT operations We discuss three possible technology components that would improve the operational performance of data centers: (1) integration of renewable energy sources (2) increasing energy efficiency through IT consolidation and workload optimization, and (3) multifunctional sensor networks for better cooling and infrastructure management We discuss the key requirements and how these technologies can be combined to achieve a sustainable path

Sustainable data centers powered by renewable energy

Hotspots in data center have been attributed to an increase in equipment failures, which causes system down time and business loss. In maintenance of IT equipment, removing hotspot with minimal cooling power cost is both ecological and financial benefits. Thus, identifying root cause of hotspots in data center is essential. A variety of factors can cause the issue, and therefore, diagnosing root cause of hotspot for removing and preventing it becomes complicated. This paper proposes a technique which supports diagnose the hotspot from logical level relative to physical conditions. In the proposed technique, performance and configuration data of each potential factor are analyzed with hotspot trochoid automatically. Effect and impact of the factor are synthesis evaluated for each component to diagnose whether it is related to the hotspot emerging or not. The diagnosis results are collected for suspects of creating hotspot in the target ambient, and then, the suspects in the whole system can be ranked for helping to identify the root cause. Hotspot diagnosis from the logical level is also useful to improve the hotspot diagnosis on other external physical conditions factors, when the logical causes are excluded by the proposed approach.

Stephan Barabasi

Papers

Sustainable data centers powered by renewable energy

Hotspot diagnosis on logical level