Energy-efficient server clusters

Mootaz elnozahy, Michael D. Kistler, RAMAKRISHNAN RAJAMONY

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

259 Scopus citations


This paper evaluates five policies for cluster-wide power management in server farms. The policies employ various combinations of dynamic voltage scaling and node vary-on/vary-off (VOVO) to reduce the aggregate power consumption of a server cluster during periods of reduced workload. We evaluate the policies using a validated simulator that calculates the energy usage and response times of a Web server cluster serving traces culled from real-life Web server workloads. Our results show that a relatively simple policy of independent dynamic voltage scaling on each server node can achieve savings ranging up to 29% and is competitive with more complex schemes for some workloads. A policy that brings nodes online and takes them offline depending on the workload intensity also produces significant savings up to 42%. The largest savings are obtained by using a coordinated voltage scaling policy in conjunction with VOVO. This policy provides up to 18% more savings than just using VOVO in isolation. All five policies maintain server response times within acceptable norms.
Original languageEnglish (US)
Title of host publicationPower-Aware Computer Systems - 2nd International Workshop, PACS 2002, Revised Papers
Number of pages19
ISBN (Print)3540010289, 9783540010289
StatePublished - 2003
Externally publishedYes

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)


  • Clusters
  • Power Management
  • Voltage Scaling
  • Web Servers


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