that the standard machine won’t have internal temperature sensors to monitor whether one of its hard disk drives might be overheating. On the other hand, Facebook’s Open Vault, a freely accessible server hardware design, has 10 thermal gauges spaced throughout. These sensors link to a self-monitor-ing system that can adjust the speed of six fans that help to ensure the server stays cool. Furthermore, the fans themselves consume less energy than the industry standard.

Efficiency for All

The Open Vault design is part of a larg-
er Facebook effort, OpenCompute,
that makes the company’s data center-
related efficiency tricks publicly avail-
able. Weihl says Facebook released
this information in part because it
does not see much of a competitive
advantage in locking up its energy-sav-
ing secrets. “We’ve done a lot of cool
things,” he says, “and the conclusion
here was that we should figure out how
to work with the industry to be as effi-
cient as possible.”
Facebook’s goal is to have a larger
impact on data center energy con-
sumption on the whole. And Weihl
says the company was thrilled to see
that server manufacturers like Dell and
Hewlett-Packard have incorporated
some of its recommendations, like the
removal of vanity plates. Such changes
could translate into warmer data cen-

At Facebook’s
Prineville, oR, facility,
ambient air flows
into the building,
passing first
through a series
of filters to remove
bugs, dust, and
other contaminants.

ters, and more savings on the cost of cooling the huge buildings.

Despite the evidence, and examples
from the efficiency leaders, many com-
panies are still afraid to turn up the
thermostat, says Schroeder. Her own re-
search suggests that this fear is unjusti-
fied. “We can safely say that increasing
the temperature by a few degrees will
not significantly increase failure rates,”
she explains, “and increasing tempera-
ture even a few degrees will save signifi-
cant amounts in cooling.”
Koomey argues a number of road-
blocks remain. For instance, tradi-
tional data centers can last for 15 to 20

years, preventing the wholesale adoption of the more efficient new designs, and many of these older facilities are filled with “comatose” servers that suck up power but no longer handle any computation. “There’s still a long way to go,” he says.

 

Further Reading

Barroso, L.A. and Urs Hölzle, U. The Data Center as a Computer: An Introduction to the Design of Warehouse-Scale Machines, Morgan & Claypool Publishers, San Francisco, CA, 2009. El-Sayed, N., Stefanovici, I., Amvrosiadis, G., Hwang, A., and Schroeder, B. Temperature management in data centers: Why some (might) like it hot, Proceedings of the 12th ACM SIGME TRICS/ Performance Joint International Conference on Measurement and Modeling of Computer Systems, June 11–15, 2012, London, England. Google, Inc. Google’s hamina data center, http://www. youtube.com/watch?v=VChOEvKicQQ&featu re=player_embedded, May 23, 2011. Hamilton, J. Perspectives, a blog by Amazon Web Services infrastructure efficiency expert James hamilton, http://perspectives. mvdirona.com/. Koomey, J. Growth in Data Center Electricity Use 2005 to 2010, Analytics Press, Oakland, CA, 2011.

Gregory Mone is a boston, Ma-based science and technology writer and the author of the novel Dangerous Waters.

© 2012 aCM 0001-0782/12/10 $15.00

Privacy
Vehicle License Plates and Surveillance

systems for reading, matching, and storing vehicle license plate data are proliferating, with automatic license-plate reader (Alpr) cameras being deployed by law enforcement agencies at all levels of government, often without the knowledge of the populations under surveillance.

Alpr cameras, on stationary
objects or atop police cars, can
photograph hundreds of license
plates per minute. the license
plate numbers are converted
into machine-readable text and
matched against crime databases,
alerting a patrol officer when a
“hit” appears. the data, which
includes gps location, time,
and date, is generally kept for
every reading, and often for an
indefinite period.

the online computer technology journal Ars Technica recently reported on an Alpr system in california that produced numerous false positives, and which failed to read the license plate on a reporter’s car. the false positives stemmed from the fact that the california department of Motor Vehicles takes a long time to update its vehicle-crime database, and