The Case for Power Management in Web Servers

  • Pat Bohrer
  • Elmootazbellah N. Elnozahy
  • Tom Keller
  • Michael Kistler
  • Charles Lefurgy
  • Chandler McDowell
  • Ram Rajamony
Part of the Series in Computer Science book series (SCS)


Power management has traditionally focused on portable and handheld devices. This paper breaks with tradition and presents a case for managing power consumption in web servers. Web servers experience large periods of low utilization, presenting an opportunity for using power management to reduce energy consumption with minimal performance impact. We measured the energy consumption of a “typical” web server under a variety of workloads derived from access logs of real websites, including the 1998 Winter Olympics web site. Our measurements show that the CPU is the largest consumer of power for typical web servers today.

We have also created a power simulator for web serving workloads that estimates CPU energy consumption with less than 5.7% error for our workloads. The simulator is fast, processing over 75,000 requests / second on a 866MHz uniprocessor machine. Using the simulator, we quantify the potential benefits of dynamically scaling the processor voltage and frequency, a power management technique that is traditionally found only in handheld devices. We find that dynamic voltage and frequency scaling is highly effective for saving energy with moderately intense web workloads, saving from 23% to 36% of the CPU energy while keeping server responsiveness within reasonable limits.


Power Management Request Rate Dynamic Voltage Scaling Power Management Technique Power Management Policy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • Pat Bohrer
    • 1
  • Elmootazbellah N. Elnozahy
    • 1
  • Tom Keller
    • 1
  • Michael Kistler
    • 1
  • Charles Lefurgy
    • 1
  • Chandler McDowell
    • 1
  • Ram Rajamony
    • 1
  1. 1.IBM ResearchAustinUSA

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