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Power Management in Data Centers

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PCQ Bureau
New Update

Akey element of every data center's physical infrastructure is power, which

needs to be provided continuously to the equipment to ensure uninterrupted

services. Unfortunately, this is easier said than done due to many reasons. One

of them is the dynamic nature of data centers today.

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Continuously, there's more equipment being added in data centers, which

requires the requisite power to scale up accordingly. So obviously, if you've

deployed a large, monolithic power management solution which can't be scaled

with the requirement, then you're in for trouble. What's required is a modular

power distribution and backup system, which can scale up with the



requirements.

Modular power units however, are not sufficient to cope up with the other key

trends taking shape in data centers. For instance, power density per rack is

also increasing in data centers thanks to the use of blade servers. Besides

raising the power requirements, denser racks also lead to greater heat

dissipation, thereby stretching the cooling system. The cooling system in turn

also requires better power management to continuously do its work. So once

again, it indirectly boils down to efficient power management and provisioning.

Another key trend that's related to data centers is IT infrastructure

consolidation. Increasingly, organizations are preferring a centralized IT

infrastructure over a distributed one. This improves the manageability, reduces

costs, and improves uptime of the IT infrastructure. At the same time however,

it requires better power management, because you're in a way putting all your

eggs in one basket. Power failure could have a drastic impact on your

organization's business.

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All these trends have nearly doubled the energy consumption of data centers

over the past few years. In fact, as a thumb rule, half of the total energy

consumed in a data center is by the IT equipment alone. Unlike other equipment,

IT equipment requires cleaner power and better monitoring becaue it's more prone

to failure. So a combination of these factors is forcing IT departments globally

to monitor data center power consumption and find ways of increasing energy

efficiency.

In this article, we'll not talk about the backup solutions like UPSes that

can be used in data centers for cleaner power and backup. Enough has been

written about them by us as well as other media in the past. It would suffice to

say that you need a scalable UPS system, which can easily grow with your IT

requirements. So in this article, we'll focus on other aspects of power

monitoring and management, which starts from choosing the right IT equipment

itself, and then moves towards implementing solutions that can monitor and

manage the power distribution to them. So let's start with the equipment.

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Choice of IT equipment



Most IT vendors today are harping about providing energy efficient hardware,
whether it's servers, storage, networking, or security. So before you can work

out a proper power management strategy for your data center, you need to study

the power consumption patterns of your existing equipment. Work out a strategy

to gradually phase out all energy efficient equipment and replace with energy

efficient ones. For instance, multi-core processors have caused a revolutoin in

the server space, by adding more compute capability within the same form factor.

You no longer need to invest in a bigger server box if you want more power. So

if you haven't already, you need to work out a strategy for replacing existing

servers in your data center with multi-core ones. Next, work out similar

strategies for other equipment, e.g. moving to Network Attached or centralized

storage over direct storage, to get better power consumption per Terabyte.

Using power saving technologies comes next. Server virtualization fits the

bill just fine, as it allows you to improve the utilization of your existing

servers, thereby reducing the need to purchase more boxes.

Once you've optimized the power consumption of the equipment in your data

center, you're ready to monitor its power usage.

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Using power management software



With so much IT equipment, it becomes essential to monitor the power being
provided to them. Here you could go for direct or network attached power

monitoring solutions. It would keep track of peak and idle load on servers. When

the server is not in use, it could reduce the power supplied to it and vice

versa.

Moreover, today, you can get software that let's an administrator set

different power mgmt policies. You can also use software to keep track of energy

being utilized by different equipment and plan a solution to minimize

consumption.

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Remote power management



Administrators can implement different hardware solutions to remotely manage the
power of equipment in the data center. Servers can be remotely switched on/off

or restarted. These solutions also provide you with the choice to restrict power

to any device.

Smart load shedding



Certain power management hardware equipment have embedded smart load shedding
features. Using this feature, non-essential equipment can be turned off when not

in use. Such a feature is quite useful in situations when mains supply is not

available. Turning off non-essential equipment would then improve the back-up

time of a UPS.

Three-phase power



Implementing 3-phase 208 V power supply helps consolidate power needs and it is
also simpler to implement and maintain as it uses fewer circuits as compared to

single phase power supply. This results in overall reduction of power

distribution units required to power the equipment and increase the available

amperage for each server rack.

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DC power distribution systems



Such a system helps reduce power consumption as conversion from AC to DC occurs
only once at the main input to the building. The DC is fed directly to the

servers and it also keeps the battery charged.

DC-powered servers don't have power supplies built-in but these are

provisioned for elsewhere in the infrastructure. Using DC supply does away with

the need for extra conversion. But this technology is suitable only for large

data centers and there are not too many experienced people out there to handle

such systems.

Designing an efficient system



The common design problems that lead to reduction in efficiency are:


1. Power distribution units and transformers operating well below their full
load capacities.



2. Air conditioners for heating and cooling being used at the same place.


3. Tampering with the throttle valves of cooling pumps considerably reduces
their efficiency.



The solution to these problems is to create a well-structured/tested design

that places each of the equipment in the right order.

Employing effective cooling solutions



Cooling systems consume a considerable amount of the total energy consumed.
Therefore effective cooling solutions should be used so that there's no wastage

of power. Row oriented cooling has higher efficiency for high density. Shorter

air paths require less fan power. An effective floor layout plays an important

role in increasing the efficiency of cooling solutions.

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