Data Center EfficiencyThe Google way.

Arjun MohanHima SudarsanNithin MadhavanSurej Shams

BackgroundMajor data centers require a large

amount of energy to power and maintain them.

The cost of running large data centers is a significant component of the overall IT budget of firms.

There are two components to the energy cost of data centers:

Cost of running computers. Cost of cooling them.

In 2011, the EPA estimated that data centers in the U.S. used about 12 GW of power, equivalent to the output of 25 major power plants.

Due to increasing power demands, by 2020, the world's computer servers will match or exceed the carbon emissions of the airline industry.

Ways to go Green

Methods to reduce power consumption.

Distribute data centers worldwide, placing them in areas where it’s more efficient to power them.

Use of hydropower.Virtualization.

Google is an industry leader in data center efficiency.

It builds its own custom data centers rather than rely on standard industry equipment and practices.

Q. 1

What is PUE, and why is it an important place to start when considering how to reduce data center power consumption? What value of PUE should data center managers strive for?

• Power Usage Effectiveness (PUE) is a measure of how efficiently a computer data center uses its power.• It is the ratio of total amount of power used by a computer data center facility to the power delivered to computing equipment.• PUE was developed by a consortium called The Green Grid.

• The data center industry uses PUE to measure efficiency.

• It help reduce the energy used for non-computing functions like cooling and power distribution.

• A PUE of 2.0 means that for every watt of IT power, an additional watt is consumed to cool and distribute power to the IT equipment.

A PUE of 1.0 is considered to be ideal.

A PUE closer to 1.0 means nearly all of the energy is used for computing.

For using PUE effectively, it's important to measure often.

It should be sampled at least once per second.

Q. 2

Describe the five methods recommended by Google for reducing power consumption.

Google recommends five methods for reducing power consumption:1. Measure PUE2. Manage airflow3. Adjust thermostat4. Use free cooling5. Optimize power distribution

1.Measure PUE• Power usage

effectiveness (PUE) is a measure of how efficiently a computer data center uses its power.

• PUE measures the amount of non-computing overhead energy to the amount of energy used to power the actual machines.

2. Manage airflow• Good air flow is fundamental to

efficient data center operation. • For healthy server and computer

function the internal temperature of the data center is to be kept at the right level.

• First thermal modeling is used to locate hot spots and better understand the air flow in data centers.

• Then simple, cost-effective tactics to prevent hot air from mixing with the cold.

Use blanking panels (or flat sheets of metal) to close off empty rack slots and prevent hot aisle air from seeping into to the cold aisle.

Hang plastic curtains (like those used in commercial refrigerators) to seal off the cold aisle.

Enclose areas with components that run hotter (such as power supply units or PSUs) with plastic curtains.

3. Adjust thermostat• A thermostat is a control unit for a heating or cooling system or a component part of a heater or air conditioner• Senses the temperature of a system so that the system's temperature is maintained near a desired set point.• The need for energy intensive air conditioning is eliminated by raising the cold aisle of the data center to 80°F or higher.• This helps to reduce energy use significantly.

 

4.Use free cooling•Free cooling is removing heat from a data center without using a large air-conditioner, or chiller.• Cold outside air, water evaporation, or thermal reservoirs are used to cool the equipment. • Avoiding the need for mechanical chillers is one of the best way for energy and cost savings.

5. Optimize power distribution• To optimize power distribution, Google

use high-efficiency power supplies, minimize the number of times power is being converted from one type of electrical current to another, and keep power supplies as close to the load as possible.

• The servers lose only a little over 15% of the electricity they pull from the wall during power conversion steps—less than half of what is lost in a typical server.

Q. 3

How much of the world’s global greenhouse gases are the result of computing? List several factors thatwill tend to retard or accelerate data center power consumption both globally and in the United States.

Around 2% of the global

greenhouse gas emissions are a

result of computing.

In this 2%, 15% constitutes data

centers and 5 % includes large

internet data centers.

Factors that accelerate power consumption

Advancements in IT.

Cloud computing.

Audio and Video streaming.

Factors that reduce power

consumption

Air management

Chillers

Virtualization.

This technique allows servers to

perform multiple tasks at once.

Distributing datacenters worldwide.

Q. 4

Data center power consumption will be high in developed countries, because most of the major data centers are located in these countries.

Now, to reduce data center power consumption, companies are preferring places with lower ambient temperatures. This includes, Iceland and Scandinavia.

This map shows Google’s data center locations worldwide.

The map shows that a large number of data centers are located in North America and Europe.

This will include most of the developed countries.

Q. 5Imagine that a company has

developed an advanced technology that allows it to reduce its data center requirements by an unprecedented amount, and creates a competitive advantage for the company in the data center market. Why should it share that technology with other data center firms?

If a firm share its techniques, the rest of the industry can also be more efficient centers, and decrease global emissions of green house gases.

Google is considered to be an industry leader in data center efficiency.

It builds its own custom data centers. But Google will not share its

virtualization technology.

Google takes many other steps to share its energy efficient best practices with other firms and the public.

Q. 6Should the government or an

industry association regulate the carbon emissions of the data center industry as they do the airline industry? Or the automobile industry? Or is it sufficient to rely on the competitive market place to drive down energy consumption in data centers?

A government or an industry association should regulate the carbon emissions of the data center industry as they do for other industries.

Such an association can make the companies aware about the importance of ‘going green’ and there by reducing emissions.

The Environmental Protection Agency, In 2007, projected that the power requirements of data centers would double from 2005 to 2010.

There is plenty of incentive for online e-commerce companies to reduce their data center power consumption.

In addition, competition among the industry’s largest providers of data centers are incentivized to help their customers “go green” and reduce costs.

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