D ATA C E N T R E S
An area that must not be overlooked
is the impact of the power testing on
the switchgear. Running the testing at
maximum load for an extended time
will show if there is risk of damage to
the switchgear that has been installed.
It will also indicate a fire risk, so
temperatures across critical components
must be monitored constantly.
Level 3: IT Systems
This is where the most mistakes are
made. You don’t want equipment that
creates spot heat or that cannot be run
for extended periods without a risk of
failure or even fire. The heat generated
must match the expected IT load as
much as possible and be deployed at
different heights in the data centre.
The correct approach is to use
industrial heating systems placed
throughout the facility that run at
different loads. Typically these range
from 15kw and 22kw. However, changes
in data centre loads mean that 50kw and
100kw is now being used to simulate
denser equipment such as converged
systems and racks of hyper-converged
servers.
Additional testing around both
electrical and cooling systems now
takes place. It will identify whether the
effectiveness of the internal airflow, in
and out, is balanced. It also ensures
the electrical distribution systems and
backup electrical systems are working
correctly.
Level 4: Granular Testing
This part of the test programme
focuses on the deployment scenarios for
hardware. The facility owner needs to
provide as much detail as possible on
what is likely to be deployed and where.
The type of system and how heavily
it is used will allow testing to simulate
load as close as possible to real life. If
38 NETCOMMS europe Volume V Issue 6 2015
You must test the entire facility in order to understand where problems may strike
aisle containment is to be used, build
temporary aisles and test the cooling to
ensure the input and output air systems
work correctly. If the racks and other
infrastructure are available these should
be installed and used for all the power
and cooling tests.
Use rack mounted server emulators
to provide the load for different types
of IT equipment, such as blade servers,
racks servers, converged systems and
storage systems. They allow a more
accurate test of where heat is generated
and how it is removed from the data
hall. It is essential that at this point the
testing of power and cooling systems
include the entire facility from chillers
and generators to floor tiles and power
strips.
Always compare the testing against
the computational fluid dynamic model
built to predict how the air will move
in the data centre. Minor differences
are common and often caused by
changes in how infrastructure is placed.
Significant differences highlight errors in
the planning of the facility or the testing.
This provides a final chance to correct
things before handing the facility over to
the customer.
Conclusion
This article is just a brief look at a four
level approach to testing a data centre.
The key takeaway is that you must test
the entire facility in order to understand
where problems may be waiting to
strike. As data centres move towards
being hyper-scale facilities where they
are heavily automated, the need to get
the power and cooling tests right first
time and to identify the weaknesses or
potential bottlenecks becomes essential.
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