@article {43, title = {Optimality analysis of energy-performance trade-off for server farm management}, journal = {Performance Evaluation}, volume = {67}, year = {2010}, month = {11/2010}, chapter = {1155}, abstract = {

A central question in designing server farms today is how to efficiently provision the number of servers to extract the best performance under unpredictable demand patterns while not wasting energy. While one would like to turn servers off when they become idle to save energy, the large setup cost (both, in terms of setup time and energy penalty) needed to switch the server back on can adversely affect performance. The problem is made more complex by the fact that today{\textquoteright}s servers provide multiple sleep or standby states which trade off the setup cost with the power consumed while the server is {\textquoteleft}sleeping{\textquoteright}. With so many controls, finding the optimal server farm management policy is an almost intractable problem {\textemdash} How many servers should be on at any given time, how many should be off, and how many should be in some sleep state?

In this paper, we employ the popular metric of Energy-Response time Product (ERP) to capture the energy-performance trade-off, and present the first theoretical results on the optimality of server farm management policies. For a stationary demand pattern, we prove that there exists a very small, natural class of policies that always contains the optimal policy for a single server, and conjecture it to contain a near-optimal policy for multi-server systems. For time-varying demand patterns, we propose a simple, traffic-oblivious policy and provide analytical and empirical evidence for its near-optimality.

}, doi = {10.1016/j.peva.2010.08.009}, url = {http://www3.cs.stonybrook.edu/~anshul/perf_power_2010.pdf}, author = {Anshul Gandhi and Varun Gupta and Mor Harchol-Balter and Michael Kozuch} } @article {58, title = {Optimizing Energy and Performance for Server-Class File System Workloads}, journal = {ACM Transactions on Storage (TOS {\textquoteright}10)}, volume = {6}, year = {2010}, month = {09/2010}, abstract = {

Recently, power has emerged as a critical factor in designing components of storage systems, especially for power-hungry data centers. While there is some research into power-aware storage stack components, there are no systematic studies evaluating each component{\textquoteright}s impact separately. Various factors like workloads, hardware configurations, and software configurations impact the performance and energy efficiency of the system. This article evaluates the file system{\textquoteright}s impact on energy consumption and performance. We studied several popular Linux file systems, with various mount and format options, using the FileBench workload generator to emulate four server workloads: Web, database, mail, and fileserver, on two different hardware configurations. The file system design, implementation, and available features have a significant effect on CPU/disk utilization, and hence on performance and power. We discovered that default file system options are often suboptimal, and even poor. In this article we show that a careful matching of expected workloads and hardware configuration to a single software configuration{\textemdash}the file system{\textemdash}can improve power-performance efficiency by a factor ranging from 1.05 to 9.4 times.

}, url = {http://dl.acm.org/citation.cfm?id=1837918}, author = {Priya Sehgal and Vasily Tarasov and Erez Zadok} } @mastersthesis {67, title = {Optimizing Energy and Performance for Server-Class File System Workloads}, volume = {Master of Science}, year = {2010}, month = {05/2010}, pages = {33}, school = {Stony Brook University}, type = {Master of Science Degree Thesis}, address = {Stony Brook, NY}, abstract = {

Recently, power has emerged as a critical factor in designing components of storage systems, especially for power-hungry data centers. While there is some research into power-aware storage stack components, there are no systematic studies evaluating each component{\textquoteright}s impact separately. Various factors like workloads, hardware configurations, and software configurations impact the performance and energy efficiency of the system. This thesis evaluates the file system{\textquoteright}s impact on energy consumption and performance. We studied several popular Linux file systems, with various mount and format options, using the FileBench workload generator to emulate four server workloads: Web, database, mail, and file server, on two different hardware configurations. The file system design, implementation, and available features have a significant effect on CPU/disk utilization, and hence on performance and power. We discovered that default file system options are often suboptimal, and even poor. In this thesis we show that a careful matching of expected workloads and hardware configuration to a single software configuration{\textemdash}the file system{\textemdash}can improve power-performance efficiency by a factor ranging from 1.05 to 9.4 times.

}, url = {http://www.fsl.cs.stonybrook.edu/docs/priya-thesis/priya_thesis.pdf}, author = {Priya Sehgal} }