Data
Center Design
The
need for data servers is constantly growing. Take for example Facebook or
Google and try to visualise the size and the number of data centers that these
companies need to run their daily activities and to process the amount of information
available on their webpages.
The
phenomenon is huge and the implications on the environment are considerable due
to the important use of resources (energy and water). To give you a rough idea,
in 2007 the entire information and communication technology sector represents
approximately 2% of the global greenhouse gas emission, about 14% of this
amount was due to data centers[1]. Optimizing the resources consumption is not
only important from an environmental perspective, it can also enable savings of
millions of dollars at a global scale.
In
the following few paragraphs will give you
a brief introduction to data center design by going through the Google
data center best practices[2]:
1)
Measure PUE
The first important point is to have the required
instruments to measure the Power Usage Efficiency (“PUE”) equivalent to
the Total Facility Energy divided by the IT Equipment Energy.
PUE = Total
Facility Energy
IT Equipment Energy
This figure measures the effectiveness of the delivery
of power in cooling to the IT equipment. It is important to measure this ratio
to be able to keep track on the level of efficiency of the power used. The
closer this number gets to 1.00, the better.
2)
Manage Air Flow
To properly manage the air flow in your data center,
you will have to elimitate the mixing of hot and cold air flows. There are
several ways to achieve such a containment, but it is paramount to first
analyse and understand how the air flows between the data servers. Google has
been able to save USD 65’000 in energy costs yearly by investing USD 25’000
(one time investment) in components enabling such a containment of the air
flows.
3)
Adjust Thermostat
To the contrary of what has been believed for long by data
center managers, Google raises the temperature of the cold aisle which results
in a reduction of the facility energy use.
4)
Use Free Cooling
It is recommended to use the “free cooling” available
from lower ambient temperatures outside of the data center to avoid the
requirement of energy intensive cooling systems. For example, Google uses see
water cooling in Finland where the water comes from the nearby bay.
5)
Optimize Power Distribution
Losses occur in the power distribution at each step of
the a power conversion. If you eliminate a power conversion step, you spare
energy. Google has achieve this by reducing the steps at the level of the
Uninterruptible Power Supply (“UPS”) which is the system enabling the
servers to continue to run in case of electricity interruption. By putting
batteries directly into the servers, it reduces three steps of unnecessary
power conversions. With this method, Google saves USD 30 per year and per
sever!
We
are thrilled to follow the evolution and see when Google will achieve a PUE of
1.00!
See how Google follows these PUE measurements:
