Green It From PaGe 25
on the greenness of their products. It is tips for greening the server room
important for IT managers to test network equipment in a production environment to get accurate numbers of The three biggest power
performance per watt. users in the data center are While some vendors provide informa- reported to be servers, at Baffle Hot air return Baffle
tion on network equipment at various 31 percent, followed by HVAC
load levels, these tests are almost always and then disk storage.
performed using test loads for relatively Networking equipment
short durations. came in at fourth at 14 percent of energy usage. Switch
The lab at e WEEK is kept cool at 70 F, but experiments at Intel show that “cold”
might be as hot as 90 F, yielding considerable utility cost savings.
CPU power throttling can
reduce power use by 21 percent,
but it is not widely used. This is
the low-hanging fruit for data
center operators.
For example, in my tests of Cisco Systems’ 4900M 10 Gigabit Ethernet data
center switch, I gathered my perfor- Use blank plates to Servers
mance statistics using steady workloads close gaps between racked equipment.
running in 5- or 10-minute durations.
Measurements taken every few seconds KVM tray
over a day or, better yet, a week would yield much more accurate numbers for Cold aisle
understanding long-term power use. (See Servers
e WEEK Labs’ review of the Cisco 4900M at
www.eweek.com/c/a/IT-Infrastructure/
Cisco-Catalyst-4900M-Helps-Clear-the- Storage
New data center hardware is
reported to save 16 percent over
the cost of powering existing
systems. Also, new hardware will
likely have virtualization
extensions and other power
management features.
Cold aisle
Way-to-10G/.)
Plug holes and crevices
that allow cold air to escape
from the cold aisle.
Lights out
Power distribution
The single most effective energy-sav- Minimize hot and cold ing strategy for user devices is to turn air mixing by installing Hot
them off when they are not in use. baffles in raised floors According to the EMA study refer- and ceiling plenums. aisle
enced earlier, desktop systems are left
on when not in use during evenings and UPS
weekends 43 percent of the time. The
wasted energy of this practice costs Forced cold air Baffle about $150 per system per year. raised floor Baffle
Replace dumb power
distribution units with smart
equipment that can measure
and report electrical use on
a per-outlet basis. You can
monitor a representative
sample; it’s not necessary to
smart-enable every outlet.
Manage air flow by
putting equipment as close
as possible to air handling
systems.
Forced cold air
Conversely, laptops are much less Source: e WEEK reporting and Enterprise Management Associates’ “The True Value of Green IT,” Sept. 2008
likely to be left on ContInued on PaGe 27
