Toward a Greener DataCenter

It was on my hit list for quite a while and I have been closely watching this

positive trend of growing affinity for 'green', from both sides, be it users or

manufacturers of data center equipment. But, when my protagonist, Mr Amitabh

Bachchan, propagated the message of Global Cool, at the recently held IIFA

awards ceremony, in the picturesque county of Yorkshire in northern England, I

could not resist the idea of a green story. While Global Cool talks of

eco-homes, green fuels in airlines, etc, our agenda is data centers.

The impulsion



Ever since the days of Industrial Revolution or may be earlier, we have been

hearing horror stories of how mankind will suffer from overuse of technology.

That our natural resources will quickly deplete causing an 'immediate' threat to

us. Oil wars further fueled the stories around oil crisis. Later on, we heard of

the greenhouse effect, ozone layer depletion, global warming, etc. We've been

hearing all this for ages. The general thought process is that it's an old

tussle and will continue. 'No, the sky is not falling', then why should one

bother? If there will be no electricity or no oil, there will be something to

source up my car or for that matter, even my data center. Scientists are already

working on renewable and other sources of energy. They will find a way out, so

there's no need to worry. We have plenty of time. BUT, do you really know 'how

much time'? Unfortunately not, and it's because of this very reason that most

people end up becoming complacent and don't bother about energy saving. But if

you really look at it, then this is also the very reason you must start planning

for it right now. Most data centers around the world have started becoming more

energy efficient and what's more, they're even reaping business benefits out of

it. It will not be long before one starts seeing a similar trend in India as

well. There's enough buzz and concern in the market around energy consumption to

drive it through. It therefore makes sense to start planning for it,

immediately, so that you don't lag behind.

Why have green data centers?



In data centers, it used to be the floor space that was at premium, but lately

power availability has started to appear as a bigger concern. The reason is

simple. As your business grows, you keep adding more servers, storage,

networking, and other equipment in your data center. Then, in order to keep them

all running, you add more power management devices, and finally, add more air

conditioning to keep them cool. Before you know it, your power consumption

shoots through the roof, and so do your electricity bills. This is a cost you

can't avoid, but can definitely reduce considerably through proper planning and

using more energy efficient devices. This of course, is easier said than done,

but you need to make a start, anyways. And, who knows that may qualify you for

some tax benefits, electricity rebates or some other governmental incentives to

come in future!

Core of the problem



Since the days of yore, electrical usage was not considered as a considerable

design criterion for data centers and also, as it was incurred, was not

effectively managed as a data center expense. As a matter of fact, people

managing data centers hardly had an idea of how much electricity was being

consumed by their data center every month and who were the main culprits that

consume more power than what they should. And, to make the situation worse,

there were no proper guidelines and standards, as to what was permissible limit

for a particular piece of equipment. Sometimes, the equation would become so bad

that the cost of electricity over the life of a data center became more than the

costs of the power system and the UPS, or even more than the cost of servers and

storage.

Inventor Jay Harman of Pax Scientific has designed an energy efficient fan. He found the inspiration in the spiral flow patterns of water and air

It was hard to establish a correlation between particular decisions and their

impact on the electricity consumption. For

example, it was difficult to figure out the electrical usage implications of the

installation of a new zone of equipment in the data center or of a new

operational practice. Tools for simulating the electrical costs of data centers

were neither widely available nor very accurate and usable, offering little

motivation for getting used during data center designing.

It was also difficult to find the electrical costs of a decision, as the

electricity bills were sent out long after the actual charges were incurred. The

bills would normally land in a department, which had little or no connection

with data center administration. Even if you got to see the bills, it was

difficult to cull out the actual expense made by the data center, during a

particular course of time, as normally, you didn't get to have the separate bill

for the data

center entity.

If the things are still like this at your data center, please make up for those

and involve the top management to change the situation for better. It's wise to

be informed, while making policy

decisions. And, in case of data center it becomes more detrimental, as a wrong

decision may cost you a limb.

At the core, there are also system design issues that commonly reduce the

electrical efficiency of a data center. Generally, power distribution units are

found not utilizing their full capacities. Air conditioners are forced to drive

air over long distances, requiring them to consume more power. Cooling pumps

that use valves to automatically adjust their flow rate, usually accrue more

power than the ones that need manual intervention.

You must know how much redundancy you want in the system. N+1 or 2N redundant

designs are fine, but they result into under-utilization of components, so

better guard against too much of redundancy. Too much of oversizing of UPS

should also be avoided, unless it is operating very near its capacity limit.

Also, if you continuously run your UPS at low loads, it may affect its actual

efficiency in the long run.

Where to save energy?



Ideally, energy improvements should start from the point where data center floor
is being

designed. The planning of equipment should be done with a view of energy saving.

The hot air is directly sucked up from within the racks through closely mounted ducts instead of being thrown out into an aisle. Only cold air remains in the aisles

1. Air flow and cooling: Power conditioning equipment can consume a significant

amount of energy. However, with a little bit of planning, you can make it more

efficient. One way is to provide better coupling between the cooling equipment

and heat generating elements. Another way is to have closer coupling. There's an

improvised model of the hot aisle/cold aisle setup to do this. In this, instead

of allowing hot air to be blown out into an aisle from behind the rack, it can

be sucked up from within the racks into ducts. These ducts would then directly

send the hot air to the refrigeration unit. The aisles would thereby have only

cold air. This would reduce the cooling requirements in the data center.

Another improvisation of the hot aisle/cold aisle is to have a suspended ceiling

with a structure to suck in hot air from all the hot aisles. This will prevent

the hot air from spreading in the data center, thereby improving the cooling.

One more thing to check is the positioning of your perforated floor tiles. How

close are they to the racks? They must be close enough to blow cold air directly

into the racks.

You should also review your data center's lighting. Bulbs and tubes also

generate heat, and can stress your cooling equipment. So it's better to use more

energy efficient ones that generate less heat.

2. Through consolidation: You need to consolidate as much as possible and at as

many levels as you can. You can start with consolidation of processing power,

using server virtualization and ensure maximum utilization of server resources.

There are other things, which you may effectively try in the name of

consolidation, that include use of blade servers utilizing low-voltage

processors in place of traditional servers, use of a two-way server or a

dual-core server in place of two single-core servers or one dual-processor-based

server, and replacement of a four-way server with a two-way dual-core server.

But, the decision on such migrations should come only after taking into account

all the hassles and costs associated with them. Then, set power-saving options

of your machines 'on', and make good use of the available power management

tools. We'll explain virtualization in detail later in this article.

3. Better power supplies: You should have an eye on the power supplies, as well,

that you're procuring for your data center. Inefficient power supplies waste a

lot of energy. And, every unit of energy wasted by the inefficient power

supplies requires another unit of energy in terms of cooling to compensate for

the heat thus generated, making the wastage two-fold.

Moreover, if you follow standards and rely on certifications that certify a

machine for consuming less power, it always keeps you on the safer side. The

good news for the enterprise users is that the US Environmental Protection

Agency (EPA) has already initiated a process to develop an ENERGY STAR

specification for high-end servers. They are analyzing the viability of such a

specification in view of the existing server market dynamics, availability and

performance limitations of energy-efficient designs, and the potential energy

savings that can be incurred by the use of these designs.

Optimum utilization



Power consumption in a data

center also depends upon how well are the resources being utilized. For

instance, how well are your applications able to use the underlying hardware?

Nowadays, as servers are increasingly becoming multi-core, it's importnat that

the applications utilize all the cores. Otherwise, your servers are consuming

the same amount of power, but are not being utilized effectively. This would

reduce your server utilization. Even if you're not using multi-core servers,

it's not as if they would be utilized fully. The average utilization of a server

can be anywhere from 7 to 40%, but hardly 100% or anywhere near that. The energy

consumption however, remains the same irrespective of utilization. The solution

therefore is quite clear-virtualization. Run more operating systems and

applications per server to utilize your servers better. There is a trend towards

using server virtualization in the data center.

Even if you are not sure of running your mission-critical applications on a

virtual server, you can put your regular less-critical applications safely on a

virtual ized machine. You can hide behind the fact that mission-critical

applications are already keeping the processors engaged to around 70%, so why

put them on virtual server! Then, try dynamic virtualization and free as many

machines at a point in time, as you can, putting the free machines off for that

duration of time. For example, if the workload gets pretty low after sunset,

then consolidate the workload amongst possible lowest number of servers and set

the remaining to rest.

Vendor initiatives



Today, each IT vendor worth its name is pushing for more energy efficient data

centers. Let's take a glimpse. And trust me these are only a few which I know or

was able to recall here. Pardon me for my affinity for the world of

storage.

We have heard of Intel Xeon, AMD Opteron, IBM Power series and Sun UltraSPARC

T1, each claiming to be the best in terms of power-efficiency. But, how many of

us have heard of PWRficient by P.A. Semi, a Santa Clara, Calif.-based start-up.

Not long ago, HP announced its new power-saving (Adaptive Infrastructure)

technology for storage arrays. If claims are to be believed, then this new

technology will cut down power and cooling costs by 50%. IBM is well known for

its Project Green and is putting in a lot of money to fund this project, which

aims at making data centers greener. IBM has launched this initiative as part of

their global Intelligent Energy campaign, aimed at helping economies cope with

the existing and impending energy crisis. Hitachi Data Systems has introduced

intelligent virtual storage controllers and software for Dynamic Provisioning,

which again are energy saving propositions.

EMC, for its Symmetrix DMX storage, has gone for 500 GB disk drives that offer

67% more capacity than a 300 GB disk drive, but consume same power and do not

crave for more space. We have heard of Copan Systems using a massive array of

idle disks (MAID) architecture, resulting into an energy-efficient storage

array. It only keeps the power on for up to one-fourth of the drives at a time

to improve power utilization. This also extends the lives of the disk drives, as

they now have to work in shifts of six hours a day! The company had been able to

accommodate 896 drives in a working array, increasing the disk-density to

approximately four times (compare with an average array having 250 odd disks)

and using the same amount of power. The array can be used to serve as a virtual

tape library (VTL) or an archiving platform.

The hot air is sucked up by a chimney-like opennings put on the suspended ceiling, which is then directly sent back to the refrigeration units

Nexsan Technologies is also boasting of AutoMAID, part of its SATABeast

offering, which automatically switches off the idle drives and reduces power

consumption. Users can configure the system for power savings, according to

their response time requirements. It is almost analogous to the power saving

mode of a notebook. According to the claims made by the company you can save up

to 30% on power consumption, if you set the drives to rotate at 4,000 rpm, after

being idle for 5 minutes. This will however hamper the data recovery time a bit.

Similarly, if you put the drives to spin down completely, after a certain idle

period, the data recovery time goes on the order of 30 seconds. Trade-off is in

your hand.

Concepts like 'thin provisioning' and 'sparse volumes' have started hitting CIOs'

desks. After all they promise ultimate storage utilization efficiency, without

heavy administrative overhead. Under thin provisioning you need to buy storage

only when it is essentially required. Logical volumes are allocated to

applications as per current and future needs, but physical storage is pushed in

only when the existing storage falls short. There is an aggregated pool of

storage, which reduces the chance of finding an unused drive in a data center,

sucking up resources, such as electricity, space etc. Vendors promoting this

approach include 3Par, Compellent, Cloverleaf, DataCore, LeftHand Networks and

NetApp.

Another storage player from the US, Pillar Data Systems, has blown up the

concept of 'sleepy drives', ie, slowing down of drives that are long idle. Such

developments made by array vendors outrightly denounce the fatalistic notion

that nothing can be done to save energy from storage as disks just need to be

kept spinning.

Beyond ensuring optimum utilization, storage managers should also look for a

suitable storage solution, in the very first place. When you don't need high

performance from storage, choose disks that rotate at slower rates, may be 7,200

rpm or 10,000 rpm. In such cases don't insist on a 15,000 rpm model; slower the

rotation, lesser the power consumption per disk. Similarly a 2.5-inch drive

requires lesser power (nearly 5 volts) as compared to the standard 3.5-inch

drive, which consumes nearly 12 volts of power. Small form-factor drives, may

however, offer you a smaller capacity. Use of DC can also be an energy-saving

proposition, as a lot of energy gets wasted in the current-conversion itself.

Powering up the rack with DC

allows a portion of the heat to move from the servers to the rectifiers, which

may be kept out of the cool room. But, it is not the end of the problem rather

it is like cleaning a place by making another place dirty (a long-standing

personal policy for not getting my living room clean).

Conclusion



Things are fast changing especially in the US and people are getting more energy

conscious than ever before in the realm of data centers. Reason for this is

straightforward-they are confronting it directly. For them, the forces in action

are: abundant processing load; envisioned shortage of power; stricter public

rules and policies favoring the green; and also the electricity rebates that are

coming to some of them for qualified energy-efficient data centers. California's

Pacific Gas and Energy (PG&E) is offering rebates to its high-tech users as an

incentive to motivate them to cut down on power consumption. Back home there are

hardly any wake-up calls being made right now. Things are pretty laid back here,

but destined for change. Although, today reliability scores much high on CIO's

list, and energy isn't a concern for them, but the day is not far when they will

have to distinctly ponder over energy issues.

As for the energy crisis, we need to look at absolute solutions and not

trade-offs. You have to look at the big picture. For example, use of alcohol in

cars may be tempting for the reason that it's renewable. But it takes lots of

effort, water and fertilizer to grow corn, and convert it into usable fuel. The

point I want to make here evident is-if it takes more power to develop an energy

source that delivers lesser power than what was spent on its generation, then

the mere purpose of its generation gets defeated.

In the meantime, let's keep talking of 'green' (at

http://forums.pcquest.com, under



Implementation->Technology & tech trends->What are you doing to make your
datacenter GREEN?). For whatever reasons we may talk of green, it needs a

mention and more than that a resolution from all of us, to make our planet a

greener and cooler place to live in.