Check out the new USENIX Web site.
USENIX, The Advanced Computing Systems Association

5th USENIX Conference on File and Storage Technologies Abstract

Pp. 245260 of the Proceedings

PARAID: A Gear-Shifting Power-Aware RAID

Charles Weddle, Mathew Oldham, Jin Qian, and An-I Andy Wang, Florida State University; Peter Reiher, University of California, Los Angeles; Geoff Kuenning, Harvey Mudd College


Reducing power consumption for server computers is important, since increased energy usage causes increased heat dissipation, greater cooling requirements, reduced computational density, and higher operating costs. For a typical data center, storage accounts for 27% of energy consumption. Conventional server-class RAIDs cannot easily reduce power because loads are balanced to use all disks even for light loads.

We have built the Power-Aware RAID (PARAID), which reduces energy use of commodity server-class disks without specialized hardware. PARAID uses a skewed striping pattern to adapt to the system load by varying the number of powered disks. By spinning disks down during light loads, PARAID can reduce power consumption, while still meeting performance demands, by matching the number of powered disks to the system load. Reliability is achieved by limiting disk power cycles and using different RAID encoding schemes. Based on our five-disk prototype, PARAID uses up to 34% less power than conventional RAIDs, while achieving similar performance and reliability.

  • View the full text of this paper in HTML and PDF. Listen to the presentation in MP3 format.
    Click here if you have forgotten your password Until February 2008, you will need your USENIX membership identification in order to access the full papers. The Proceedings are published as a collective work, 2007 by the USENIX Association. All Rights Reserved. Rights to individual papers remain with the author or the author's employer. Permission is granted for the noncommercial reproduction of the complete work for educational or research purposes. USENIX acknowledges all trademarks within this paper.
To become a USENIX member, please see our Membership Information.

Last changed: 4 May 2007 ac