Recent Quocirca research
shows that few data centre managers know how much power their data
centres are using - which makes it difficult for them to come up
with a well-constructed plan to optimise power consumption and
enhance their
"green" credentials. Even those who have access to the power
bill do not seem to have any granular breakdown of how that power
is being used. With data centres representing the greatest energy
spend for most large organisations, such a lack of visibility
should not be allowed to continue.
A company that is looking to address this issue is
Server Technology, Inc. - not
the most descriptive of company names, but a company that provides
a very simple but effective means of identifying what power is
really being used where and by what. As a company, Server
Technology is focused on providing equipment for monitoring and
managing power within data centres, and a major part of the
company's portfolio is based on what it calls CDUs (cabinet
distribution units) and PDUs (power distribution units).
CDUs and PDUs are essentially power distribution strips
consisting of multiple standard
International Electrotechnical
Commission (IEC) or National
Electrical Manufacturers Association (NEMA) sockets enabling
multiple electrical devices to be plugged in to a single strip - in
other words, they look and function pretty much like a multi-socket
electrical extension lead.
However, Server Technology's CDUs provide the capability to
directly measure the amount of power that is being consumed by a
chassis or an individual piece of kit. This measurement is of the
true power being used by the equipment, and as more kit is added to
a chassis or frame, its impact on the cumulative power can be
easily seen through a highly visible LED readout, or via a remote
feed capability.
All very simple and useful in seeing what power different pieces
of equipment really draw, rather than just reading the tag on the
back that gives a nominal power value based on a fully loaded
system, plus a bit for good luck. Data centre managers who use the
additive power tag approach will find that their backup power
systems may well be well over-architected for real needs. This can
have massive knock-on effects - if you believe that your backup
capability is nearing its limits, you will be loathe to add new
servers to the data centre, or will look to prioritising what
equipment has to be left to fail to leave power for mission
critical areas. All a bit of a palaver when you find that in
reality, you're only running total power of 60% of your rated
backup capability
But Quocirca believes that such measurement can have a host of
other uses. For example, your current air conditioning in the data
centre is probably sized to cool the nominal heat output of the sum
total of the power shown on the visible tags on kit. This will
generally be well over the true value, as average loads on pieces
of equipment will not be as much as the tag shows, and ancillary
equipment may not have tags to read at all. Therefore, you may be
running your air conditioning too hard for the real need - and this
has high costs associated with it.
How about equipment lifecycle under a green data centre
approach? Through a full understanding of what power is being drawn
by older equipment, plans can be put in place for older equipment
to be replaced by new, more energy efficient kit when it best fits
- not just because of some gut feel.
And for cross charging, it becomes possible to identify exactly
what power is being used by workloads that are dedicated to
specific servers - and so the business unit responsible can be
charged for that usage. One aspect of this is that the business
units may well take a decision to change its approach to lower its
power bill from the IT department, so improving the business' green
credentials further, and optimising power utilisation within the
data centre itself.
Only by fully understanding the real power draw of equipment
within the data centre can a base line be created so that plans for
improvement can be made. Only knowing what the real draw is can
lead to the optimum cooling approach being created. Knowledge of
what current loads are will provide the information you need to
manage the lifecycle of your backup power systems, and not jump too
soon to new equipment.
Through such a simple approach as using these CDU power strips,
data centre managers can gain true visibility as to their energy
usage - and do something about it.