Taming 'Power'-ful Servers

According to IDC, the worldwide installed server base
should touch 32 million this year, and according to Gartner, the total PC base
will touch 2.25 billion units by 2015. These indeed sound like impressive
figures, clearly indicating the healthy growth path that the ICT industry is
following. Unfortunately, this healthy growth path is neither 'so healthy' for
the environment nor for the energy bills of organizations! What's needed is an
effort to remain as green as possible.

Efforts are being made by hardware manufacturers to make
their products more power efficient. Processor manufacturers like Intel for
instance, have been promoting the 'performance per watt' concept, wherein the
newer CPUs give you more compute capacity, without an equivalent increase in
energy consumption. This way, when you replace your old servers with newer ones
containing more powerful, multi-core CPUs, the higher performance you'll get
won't necessarily mean an equivalent hike in your energy consumption. While
these efforts of processor manufacturers are certainly commendable, they may not
be enough for you to reduce your energy bills. For all you know, you might still
end up playing a 'zero-sum' game, wherein the total power consumed by your data
center doesn't increase or decrease. Your objective on the other hand should be
to reduce the overall energy consumption. To give you a parallel example, the
aircraft manufacturers are apparently building aircraft that will increase fuel
efficiency by 50%. Unfortunately, by the time these new aircraft replace all the
older ones, air-traffic would have doubled! So the amount of emissions in the
environment remains the same, which is certainly not desirable, and we all know
that.

Your objective therefore, should be to reduce the overall
energy consumption of your IT infrastructure, so that you can truly get
significant power savings, and reduce emissions at the same time. This will
happen by looking at other factors that could impact your servers' power
consumption. Some of these factors were highlighted during a a server workshop
that was conducted by Intel in Portland for select media from around the world.

Intel Energy Checker SDK

IBM DB2 9.7 running TPC-C benchmark at Intel Server workshop, with Intel Energy Checker SDK (lower right box) measuring work done by it. The SDK will help developers optimize DB2 code and make it more power efficient. At the Intel Server workshop in Portland, one of the things that was demoed was a SDK that will allow ISVs to measure the energy efficiency of their applications. The SDK emerged from the need amongst ISVs to make their software go green as well. Key challenges are that there's no unique definition for software energy efficiency, nor is there an industry standard to measure it. Intel defines software energy efficiency as Work divided by Energy. Here, work is the amount of useful work done by the application. The SDK measures this energy efficiency, and is also supposed to help ISVs write energy aware software. There are two key elements involved in this process. One is a custom API that interfaces with the ISVs application to measure the application's energy profile, report system productivity, and so on. Second is an energy meter, which would record the energy consumption.

Energy efficient software anyone?

Buying energy efficient hardware alone won't help you reduce power
consumption in your data center. The new joker in the pack seems to be the
software that you run on your servers. Even if your hardware is energy
efficient, it's the software that controls its utilization. We've seen it
happening in laptops for years, wherein the user controls the 'power on' states
of various devices, like LCD screen, hard drive, etc. You configure the power
settings of all these devices to get more battery backup. The same logic can be
put to use for business applications running on your servers as well. Are they
actually using the hardware efficiently, or are they just guzzling CPU clock
cycles? Maybe they can do whatever they're currently doing in fewer clock
cycles? That would certainly make the server more power efficient. The million
dollar question therefore is--how to make your applications more power
efficient? You may not have the necessary know-how to do that. This is where you
need to ask your ISVs for help. So, it's like asking for an 'energy-star'
equivalent rating for all the software you buy.

Is your software utilizing all the cores and threads?

Intel showed the results of several application benchmarks on their new
server CPUs. Some of them gave lower performance as compared to others,
primarily because they were not able to utilize all the cores and threads of the
new CPUs. There was a scalability issue. The applications were not designed with
so many CPU cores in mind. This is also understandable, because at the time of
designing the applications, even the ISVs wouldn't have expected to find so many
more cores to use in servers. So, when you buy servers with more cores, you need
to check whether your application can actually scale up to use all of them.
Check with your ISVs on the possibility of configuring their applications to
scale up with more cores. An enterprise backup application for instance, which
uses deduping to reduce redundancy in data, can certainly benefit from extra
cores.

ISVs-make software more energy efficient!

Another new demo we saw at the workshop was of a new SDK called the Intel
Energy Checker. This SDK, which is freely downloadable from Intel's site, allows
an ISV to gain greater insight into the useful work done by his applications,
thereby defining the energy efficiency. ISVs can measure the total energy
consumed (in Joules) by their application while performing a certain task. They
can then optimize their code so that the application is able to do more work
without increasing the energy consumed. Alternately, they could discover
inefficiencies in their code, which are wasting clock cycles, and actually
reduce the overall energy consumption. The SDK allows ISVs to have this insight
into the software. To read more about it, please see the box.

Memory is also a power guzzler

You never could possibly have imagined that the memory sitting inside your
servers would be a power guzzler too. During the workshop, we had a session by
Samsung, which gave us some useful insights into this area.

Come to think of it, the amount of RAM used in servers is
increasing. It's not uncommon to have servers with 16 GB memory, or even higher.
This RAM would be distributed across the server board in multiple DIMM slots.
What's more, the memory capacity in servers is increasing by leaps and bounds.
It won't be uncommon to have 64 GB memory in servers very soon, thanks to
technologies like virtualization, which would require that much memory. You
therefore obviously need to worry about the power consumed by the memory.

According to Samsung, there are studies to indicate that a
60 nm 1 GB DDR2 based server can consume up to 26% of the total power when
active for 8 hours and idle for 16 hours. This power consumption can be brought
down by using higher capacity memory  modules. Samsung says that their higher
capacity memory modules consume lesser energy than lower capacity ones. This
applies to both servers and the PC platform.

Samsung also says that you'll save energy by shifting from
DDR2 to DDR3 memory. You just need to check how much lesser power would it
consume before choosing the right one.

Other things to go green

Like CPUs, software, and memory, a similar logic can be applied to other
parts of your servers as well. More powerful servers are likely to have more
hard drives. How energy efficient are the ones in your servers? What kind of
power saving can you get by choosing more power efficient ones?

Then of course, there are other things to check like the
green IT standards followed by the equipment. Is it RoHS compliant? Is it free
from hazardous substances like lead, halogens, etc? This would help combat the
monumental problem of e-waste. Looking at each of the factors individually may
not give you significant results. That's why, you need to look at the overall
energy saving that results from all the factors. You might be in for a surprise.

Apparently, this year, half of the Forbes Global 2000 will
spend more on energy than on hardware. What's the scene with your IT
infrastructure? Time to do a reality check.

The author was hosted by Intel in Portland