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202
Managing Server Energy and Operational Costs in Hosting Centers
, 2005
"... The growing cost of tuning and managing computer systems is leading to out-sourcing of commercial services to hosting centers. These centers provision thousands of dense servers within a relatively small real-estate in order to host the applications/services of different customers who may have been ..."
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Cited by 198 (16 self)
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The growing cost of tuning and managing computer systems is leading to out-sourcing of commercial services to hosting centers. These centers provision thousands of dense servers within a relatively small real-estate in order to host the applications/services of different customers who may have been assured by a service-level agreement (SLA). Power consumption of these servers is becoming a serious concern in the design and operation of the hosting centers. The effects of high power consumption manifest not only in the costs spent in designing effective cooling systems to ward off the generated heat, but in the cost of electricity consumption itself. It is crucial to deploy power management strategies in these hosting centers to lower these costs towards enhancing profitability. At the same time, techniques for power management that include shutting down these servers and/or modulating their operational
Power and Energy Management for Server Systems
- IEEE Computer
, 2004
"... Power and energy consumption are key concerns for Internet data centers. These centers house hundreds, sometimes thousands, of servers and supporting cooling infrastructures. Research on power and energy management for servers can ease data center installation, reduce costs, and protect the environm ..."
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Cited by 143 (3 self)
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Power and energy consumption are key concerns for Internet data centers. These centers house hundreds, sometimes thousands, of servers and supporting cooling infrastructures. Research on power and energy management for servers can ease data center installation, reduce costs, and protect the environment. Given these benefits, researchers have made important strides in conserving energy in servers. Inspired by this initial progress, researchers are delving deeper into this topic. In this paper, we detail the motivation for this research, survey the previous work, describe a few ongoing efforts, and discuss the challenges that lie ahead. 1
Energy Conservation Techniques for Disk Array-Based Servers
, 2004
"... In this paper, we study energy conservation techniques for disk array-based network servers. First, we introduce a new conservation technique, called Popular Data Concentration (PDC), that migrates frequently accessed data to a subset of the disks. The goal is to skew the load towards a few of the d ..."
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Cited by 140 (9 self)
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In this paper, we study energy conservation techniques for disk array-based network servers. First, we introduce a new conservation technique, called Popular Data Concentration (PDC), that migrates frequently accessed data to a subset of the disks. The goal is to skew the load towards a few of the disks, so that others can be transitioned to low-power modes. Next, we introduce a user-level file server that takes advantage of PDC. In the context of this server, we compare PDC to the Massive Array of Idle Disks (MAID). Using a validated simulator, we evaluate these techniques for conventional and two-speed disks and a wide range of parameters. Our results for conventional disks show that PDC and MAID can only conserve energy when the load on the server is extremely low. When two-speed disks are used, both PDC and MAID can conserve significant energy with only a small fraction of delayed requests. Overall, we find that PDC achieves more consistent and robust energy savings than MAID.
Conserving disk energy in network servers
- In 17 th International Conference on Supercomputing
, 2003
"... In this paper we study four approaches to conserving disk energy in high-performance network servers. The first approach is to leverage the extensive work on laptop disks and power disks down during periods of idleness. The second approach is to replace highperformance disks with a set of lower powe ..."
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Cited by 135 (9 self)
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In this paper we study four approaches to conserving disk energy in high-performance network servers. The first approach is to leverage the extensive work on laptop disks and power disks down during periods of idleness. The second approach is to replace highperformance disks with a set of lower power disks that can achieve the same performance and reliability. The third approach is to combine high-performance and laptop disks, such that only one of these two sets of disks is powered on at a time. This approach requires the mirroring (and coherence) of all disk data on the two sets of disks. Finally, the fourth approach is to use multi-speed disks, such that each disk is slowed down for lower energy consumption during periods of light load. We demonstrate that the fourth approach is the only one that can actually provide energy savings for network servers. In fact, our results for Web and proxy servers show that the fourth approach can provide energy savings of up to 23%, in comparison to conventional servers, without any degradation in server performance.
Write Off-Loading: Practical Power Management for Enterprise Storage
"... In enterprise data centers power usage is a problem impacting server density and the total cost of ownership. Storage uses a significant fraction of the power budget and there are no widely deployed power-saving solutions for enterprise storage systems. The traditional view is that enterprise worklo ..."
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Cited by 134 (9 self)
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In enterprise data centers power usage is a problem impacting server density and the total cost of ownership. Storage uses a significant fraction of the power budget and there are no widely deployed power-saving solutions for enterprise storage systems. The traditional view is that enterprise workloads make spinning disks down ineffective because idle periods are too short. We analyzed block-level traces from 36 volumes in an enterprise data center for one week and concluded that significant idle periods exist, and that they can be further increased by modifying the read/write patterns using write off-loading. Write off-loading allows write requests on spun-down disks to be temporarily redirected to persistent storage elsewhere in the data center. The key challenge is doing this transparently and efficiently at the block level, without sacrificing consistency or failure resilience. We describe our write offloading design and implementation that achieves these goals. We evaluate it by replaying portions of our traces on a rack-based testbed. Results show that just spinning disks down when idle saves 28–36 % of energy, and write off-loading further increases the savings to 45–60%. 1
Understanding Intrinsic Characteristics and System Implications of Flash Memory based Solid State Drives
"... Flash Memory based Solid State Drive (SSD) has been called a “pivotal technology ” that could revolutionize data storage systems. Since SSD shares a common interface with the traditional hard disk drive (HDD), both physically and logically, an effective integration of SSD into the storage hierarchy ..."
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Cited by 111 (5 self)
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Flash Memory based Solid State Drive (SSD) has been called a “pivotal technology ” that could revolutionize data storage systems. Since SSD shares a common interface with the traditional hard disk drive (HDD), both physically and logically, an effective integration of SSD into the storage hierarchy is very important. However, details of SSD hardware implementations tend to be hidden behind such narrow interfaces. In fact, since sophisticated algorithms are usually, of necessity, adopted in SSD controller firmware, more complex performance dynamics are to be expected in SSD than in HDD systems. Most existing literature or product specifications on SSD just provide high-level descriptions and standard performance data, such as bandwidth and latency. In order to gain insight into the unique performance characteristics
DFTL: A Flash Translation Layer Employing Demand-based Selective Caching of Page-level Address Mappings
- Penn State University
, 2008
"... Recent technological advances in the development of flashmemory based devices have consolidated their leadership position as the preferred storage media in the embedded systems market and opened new vistas for deployment in enterprise-scale storage systems. Unlike hard disks, flash devices are free ..."
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Cited by 110 (6 self)
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Recent technological advances in the development of flashmemory based devices have consolidated their leadership position as the preferred storage media in the embedded systems market and opened new vistas for deployment in enterprise-scale storage systems. Unlike hard disks, flash devices are free from any mechanical moving parts, have no seek or rotational delays and consume lower power. However, the internal idiosyncrasies of flash technology make its performance highly dependent on workload characteristics. The poor performance of random writes has been a cause of major concern which needs to be addressed to better utilize the potential of flash in enterprise-scale environments. We examine one of the important causes of this poor performance: the design of the Flash Translation Layer
Reducing Energy Consumption of Disk Storage Using Power-Aware Cache Management
- In Proceedings of the International Symposium on High-Performance Computer Architecture (HPCA), Febuary
, 2004
"... User News) [32], today's data centers have power require-ments that range from 75 W/ft ..."
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Cited by 103 (7 self)
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User News) [32], today's data centers have power require-ments that range from 75 W/ft
Mercury and Freon: Temperature Emulation and Management for Server Systems
"... Power densities have been increasing rapidly at all levels of server systems. To counter the high temperatures resulting from these densities, systems researchers have recently started work on software-based thermal management. Unfortunately, research in this new area has been hindered by the limita ..."
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Cited by 97 (9 self)
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Power densities have been increasing rapidly at all levels of server systems. To counter the high temperatures resulting from these densities, systems researchers have recently started work on software-based thermal management. Unfortunately, research in this new area has been hindered by the limitations imposed by simulators and real measurements. In this paper, we introduce Mercury, a software suite that avoids these limitations by accurately emulating temperatures based on simple layout, hardware, and componentutilization data. Most importantly, Mercury runs the entire software stack natively, enables repeatable experiments, and allows the study of thermal emergencies without harming hardware reliability. We validate Mercury using real measurements and a widely used commercial simulator. We use Mercury to develop Freon, a system that manages thermal emergencies in a server cluster without unnecessary performance degradation. Mercury will soon become available from
Cluster-level feedback power control for performance optimization
- In HPCA
, 2008
"... Power control is becoming a key challenge for effectively operating a modern data center. In addition to reducing operation costs, precisely controlling power consumption is an essential way to avoid system failures caused by power capacity overload or overheating due to increasing highdensity. Cont ..."
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Cited by 89 (24 self)
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Power control is becoming a key challenge for effectively operating a modern data center. In addition to reducing operation costs, precisely controlling power consumption is an essential way to avoid system failures caused by power capacity overload or overheating due to increasing highdensity. Control-theoretic techniques have recently shown a lot of promise on power management thanks to their better control performance and theoretical guarantees on control accuracy and system stability. However, existing work oversimplifies the problem by controlling a single server independently from others. As a result, at the cluster level where multiple servers are correlated by common workloads and share common power supplies, power cannot be shared to improve application performance. In this paper, we propose a cluster-level power controller that shifts power among servers based on their performance needs, while controlling the total power of the cluster to be lower than a constraint. Our controller features a rigorous design based on an optimal multi-input-multi-output control theory. Empirical results demonstrate that our controller outperforms two stateof-the-art controllers, by having better application performance and more accurate power control. 1
