White Paper

Figure 5. Frequency of data center outages over two years, based on results of 2013 survey from the Ponemon Institute.
There are three factors that need to be considered for
better maintainability.
1. Overcurrent Protection Type: As mentioned earlier in this
white paper, circuit breakers are usually resettable when
they trip; while fuses usually require replacement. The
procedure for replacing fuses typically requires an electrician
and requires the input circuit to be turned off while it is
being replaced. Not only does this take time, it requires
coordination with facilities teams.
2. Modularity: Modularity along with hot swappability
ensures a faster MTTR. Look for a design with a modular
communications card which can be replaced while the
unit remains operational and providing basic power
distribution. Some rack PDUs also provide modularity of
input and output power.
3. Switching: Switching capability within a rack PDU ensures
that if connected IT gear hangs up, power can be remotely
turned on, turned off, or recycled without any physical
intervention at the data center. In order to ensure that power
to the appropriate equipment is being recycled, care should
be taken while associating rack PDU outlets to IT gear. Rack
PDUs that provide integration with data center IT equipment
access and control solutions simplify such association and
minimize the opportunity for errors.
Adaptability
As a result of the rapid pace of change that is occurring in the
data center environment, one of the biggest challenges today’s
data centers face is meeting current requirements while
ensuring the ability to adapt to future demands. In the past,
this was accomplished by oversizing infrastructure systems
and letting the data center grow into its infrastructure over
time. Many data centers are abandoning the oversizing
approach because it is inefcient in terms of both capital and
energy costs.
This also holds true at the rack level. Rack-level exibility is an
important factor in helping data centers adapt to constant
change, which often means higher densities and the demand
for greater efciency and control. The need for change can be
caused by consolidation, moving from one server or network to
another server or network, or the addition of new equipment.
For instance, to handle higher rack densities, there is a need
to seamlessly make the change while protecting the existing
investment. Intelligent, adaptive rack PDUs with separate
power entry modules provide the ability to quickly react to
this change. In addition, hot-swappable modular output power
ensures that you protect initial investment and minimize
downtime when the server architecture within the rack
changes. A modular busway system, which runs across the
top of the row or below the raised oor, can also be used to
support change by providing the exibility to add or modify
rack layouts and change receptacle requirements without
risking power system down time. (Figure 6)
12
10
8
6
4
2
2.04
2.48
5.88
6.84
10.16
11.29
0
Total DC shutdown
Extrapolated value (incidents)
for FY 2013
Extrapolated value (incidents)
for FY 2010
Localized shutdown Limited Outages
Figure 6. A modular busway system, seen here running
across the top of the rows, can be used to support power
distribution to the rack.
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