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.