With virtualization, both kinds of green are in play.

Joe Hernick, IT Director

April 30, 2009

3 Min Read

InformationWeek Green - May 4, 2009 InformationWeek Green Download the entire InformationWeek "green" issue,
our May 4 magazine distributed solely in pdf form.
(Registration required.)
We will plant a tree
for each of the first 5,000 downloads.

Want to fight global warming? Try virtualization.

The biggest marketing trumpet for virtualization has been monetary savings--physical-to-virtual conversions reduce capital expense by consolidating many servers onto fewer hosts. Additional potential savings can come from reduced management costs, less downtime, and lighter staffing.

As energy prices have fluctuated widely during the past year, CFOs are punching new holes to tighten corporate belts ever further, looking for savings wherever they can. Power and heating and cooling costs are surfacing as areas of opportunity.

That's all good for a company's bottom line. But in addition to freeing up floor and rack space, large-scale server virtualization can result in significant reductions in electrical and cooling needs. And since most of our power comes from burning fossil fuels, it's safe to say that each server is responsible for tons of carbon dioxide annually. General assessments are 4 to 12 tons of CO2 per server per year. Are swimming polar bears starting to haunt you yet?

The stats associated with virtualization vary widely, depending on who's making the pitch. For example, Oriel Technologies, an Australian VMware channel partner, proposes that paring 45 servers down to five host servers through virtualization can keep 506 tons of carbon dioxide out of the atmosphere.

I have a hard time visualizing 506 tons of CO2, so Oriel provides equivalents: planting 2,228 trees, offsetting the annual emissions of 113 cars, or, because they're Australian and it's humorous (and true), offsetting the annual emissions of 219 cows.

Whatever your view on the IT benefits of virtualization or whether you want to argue with the specifics of the assumptions in these estimates, it's tough to argue with the basic premise: Virtualization yields fewer physical servers in your data center. No matter what virtualization host platform you choose, fewer boxes equals less electricity consumed. Less electricity consumed equals fewer emissions.

VMware has taking green savings one step further. Distributed Power Management (DPM) is a new feature of its Distributed Resource Scheduler (DRS) module of ESX (and soon to be part of vSphere.) Relying on VMotion and DRS, VMware clusters can selectively shut down physical hosts as load requirements decrease, further consolidating running virtual machines to a subset of hosts. As loads ratchet up again, offline hosts power back up via wake-on-LAN, and VMs redistribute as more capacity is required. VMware projects an additional 20% power and cooling savings thanks to DPM.

Return to the story:
Rolling Review Wrap-Up: Server Virtualization Continue to the sidebar:
Our Virtual Test Drives

Read more about:


About the Author(s)

Joe Hernick

IT Director

Joe Hernick is in his seventh year as director of academic technology at Suffield Academy, where he teaches, sits on the Academic Committee, provides faculty training and is a general proponent of information literacy. He was formerly the director of IT and computer studies chair at the Loomis Chaffee School in Windsor, CT, and spent 10 years in the insurance industry as a director and program manager at CIGNA.

Never Miss a Beat: Get a snapshot of the issues affecting the IT industry straight to your inbox.

You May Also Like

More Insights