FOCUS POWER PROVISIONING
Issue 12, Oct/Nov
POWER PROVISIONING VS DEMAND Get your data center ready for the unknown by avoiding infrastructure overprovisioning and underutilization. Yevgeniy Sverdlik talks to the experts in the field to find out how
means making sure a company does not deploy more data center capacity than it needs, and that capacity can be scaled when required. This requires a delicate balancing act.
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Take the design of the electrical infrastructure, for example. Most mission- critical facilities initially come online with only a portion – often a small one – of their future capacity. So it is important to ensure the infrastructure can support the initial load without overspending on a higher-capacity system from day one. Here the system must be designed with capacity expansion in mind so it can be scaled easily in future.
Dell power and cooling portfolio manager Eric Wilcox says a typical data center uses fewer resources than its maximum capacity for most of its life. Some will never meet maximum capacity at all. “Deploying an asset that is utilized at 10% – be it UPS or copper – doesn’t make sense,” he says. “Copper’s not cheap.”
UPS capacity is one of several electrical- infrastructure elements commonly made scalable. Other components include row- level and rack-level power distribution, transformers, switchgear, incoming power panels and generator capacity.
DELL STICKS TO BOUNDARIES
Dell often re-uses existing large-scale infrastructure in its facilities. According to Wilcox, Dell’s teams have been deploying fully enclosed pods in its data centers – about 20 racks at a time.
“The larger-scale UPS [systems] already exist, so we’re using infrastructure that’s already available,” Wilcox says.
The approach may be different for new builds. While there are price advantages in buying 1MW of UPS capacity at once, there
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ne of the top concerns for today’s data center owners and operators is ensuring scarcely available capital is used efficiently. This
and one generator, and the rest of the racks are running without back-up, for which there is no need at the moment, Garcia says.
If there is a need to increase back-up in the future, however, all conduits, transfer switches, pads and breakers are in place. There is also space for another generator, and a nearby substation has enough capacity to provide another utility feed to the facility.
is a possibility the facility will go through an IT refresh and end up needing only 500kW. Another thing to consider when deciding between a large-scale, room-level UPS and a mid-size one is depreciation time.
“Your room-level UPS is considered part of your facility,” Wilcox says. “It depreciates over 20 years.” A mid-size solution is considered to be a mobile piece of IT gear and depreciates over three years. For users that deploy a small number of servers at a time, there is also a rack-level UPS.
SCALING REDUNDANCY WITH BROCADE
Brocade’s data center at its new Silicon Valley headquarters offers a great example of scaling redundancy. When designing its infrastructure, the engineers’ goal was to provide a cooling and electrical system that was maximally scalable and flexible, according to Victor Garcia, a senior facility engineering manager at the network equipment provider.
The system was built for more than 1,900 racks, about 1,560 of which were deployed in the first instance. The infrastructure was built to handle maximum capacity and the only additions needed to add more equipment are new power outlet boxes on busway tracks.
When the facility was initially brought online there was no need to provide back-up power to all racks. Only 400 racks (used for research and development) are backed up by one UPS
To ensure scalability, CRB installed two 400 amp busway systems and made provisions for an additional busway to be installed in future, when load-density requirements increased. “We’ve also made arrangements so that [all] utility transformers aren’t required on day one,” Hachem says.
The team ensured that transformer capacity could be scaled by breaking the electrical load down into equally sized segments. The space for about 2,200 racks was split into groups of about 180 racks each and the electrical system was designed so that each group was served by a separate transformer. This way the customer was able to have the utility provide only the necessary amount of transformers on day one, then add transformers gradually as requirements increased. This said, cabling
Part of the reasoning for designing the infrastructure to Tier I standard, Garcia explains, was analysis of the history of the substation that currently supplies power to the facility. “In the history of that substation there have been very [few] outages. We did the analysis and decided that Tier II was not required.”
INCREASING LOAD DENSITIES
CRB Consulting Engineers associate George Hachem says that in one of the recent projects the US design and consulting firm undertook, the engineers knew beforehand that the customer’s power-density requirement would be between 6kW and 8kW per rack, and that this would eventually increase to 10kW per rack.
MEETING THE DELICATE BALANCE OF
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