'Power and cooling heat up the Data Centre'
by Richard Fichera, Forrester

As environmental issues work their way up the boardroom agenda, attention has slowly turned to the Data Centre. Forrester's pre-emptive insight into the important role the correct running of the Data Centre can play, in reducing a company's carbon footprint, is detailed in the March 2006 report 'Power and cooling heat up the data centre', by Richard Fichera.

In addition to explaining why the Data Centre consumes such huge amounts of energy, Fichera also offers valuable advice on the practical steps companies can take to reduce the heat and power these resources consume.

Predictably, Fichera points out that despite best efforts from users and Data Centre managers, the management of heat in the Data Centre is ultimately a chain, starting with the chips, moving through the board, enclosure and rack; and ending with the Data Centre as a whole. By extension, it is only natural that the solution requires the concentrated effort from a large group of stakeholders, including cooling solution and semiconductor vendors, systems designers, software engineers, and Data Centre architects and operators. Encouragingly, however, the report notes that moves by key vendors at all points in the chain, are already yielding positive results.

Chips
The report highlights that traditionally chip manufacturers have made tradeoffs in their processor designs, allowing high leakage currents, in favour of enabling higher speeds. This wasted energy has steadily increased over time as a fraction of the total power dissipation of processors. In fact, the report predicts that, should current leakage trends continue, leakage current for a hypothetical 5 GHz chip would be approximately 50 per cent. Forrester notes, encouragingly however, that both AMD and Intel have made in-roads with more energy efficient components, namely AMD's Opteron, with its more power efficient semiconductor process, and Intel's commitment to improve its power efficiency substantially over the next 18 months.

Hardware
Currently, the report notes, the physical information stored in most configuration management products is not sufficient for optimal power and cooling decisions. The challenge of how to remove heat produced, by the chip, from the chassis to the outside environment, remains. Interestingly, Forrester predicts this issue could be resolved rapidly as vendors rush to add physical management information to their products, and Fichera points out that already both start-up vendors and established players are integrating power and cooling information into their configuration management database products.

Racks
The Data Centre racks are the place where two worlds collide, as the problems of the internal and external environments come together. Forrester correctly points out that it is here that the major bottleneck in managing the heat and power consumption of the Data Centre occurs. In theory, a standard rack can mount enough equipment to draw in excess of 25 kilowatts per rack. In practise however, the airflow limitations of most Data Centres hinders the ability to cool a standard rack dissipating more than 8KW of power. Forrester notes that further problems arise, when more powerful systems are used, increasing the amount of power per unit, but decreasing the number of units which can be stored on each rack; forcing the deployment of more racks in tight space Data Centres, or the deployment of supplemental cooling. While Data Centre design has adapted to this issue over the last couple of years, focussing on reducing obstructions to airflow, using baffles and plenums to direct airflow and designing increasingly efficient fans, Forrester predicts more help is at hand for the beleaguered Data Centre manager, as cooling systems vendors focus on the provision of supplemental cooling for very high density racks.

Yet, while this positive innovation takes place, the CIO or Data Centre manager, must still grapple with day to day issues, and Forrester offers practical recommendations that users can take, to make power efficiency an integral part of their Data Centre planning processes. Specific recommendations include:

• Researching information on power and cooling costs.
• Including power and work loads metrics like Sun's space, watts and performance metric in evaluation criteria.
• Investigating supplemental cooling for either system vendors or independent vendors.
• At a minimum, ensuring airflow and current cooling systems are operating as well as they possibly can.
• Using the process of designing new Data Centres as an opportunity to examine the trade off between denser floor space, that requires more careful management and traditional low-density designs.
• Planning carefully for modular upgrades of cooling capacity in anticipation of increased loads.

Forrester, like Logicalis, recognises the inevitable issues faced by Data Centre managers, in dealing with power and cooling in the Data Centre, and its advice is clear: If you can't stand the heat - provision for better storage and cooling.

 

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