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Environment-friendly data centers

Rising power bills and heat loads in data centers are compelling organizations to take energy saving seriously, while simultaneously contributing to a greener earth, writes Varun Aggarwal

The horrors of global warming are no longer an environmentalist’s rallying point to save the earth in the distant future. The problems exist here and now are are already haunting our present. Many organizations have taken this up as an issue that requires serious focus and are making efforts as responsible corporate citizens. Setting up green data centers is an effort in this direction.

A decade ago, the electricity bill was the last thing on any CIO’s mind while setting up a data center. The number of servers was small and the volumes of data even smaller. Even electricity was cheaper then. With India Inc soaring into stratospheric mode and adopting an inorganic growth pattern, things have dramatically changed since then, making electricity or power, a major issue in any data center.

Today’s data centers are filled with many racks of servers and switches and other equipment. The energy requirements are growing at the rate of 15 to 16 percent. The ever-increasing server load necessitates further upgrades and newer equipment. The amount of power consumed by a single data center can sometimes be as high as that required to light up an entire town.

Over the last decade, server power costs have more than doubled, placing greater stress on cooling and power infrastructure. The annual expenditure on a data center—just for cooling—reaches the multi-million dollar range. So every watt conserved provides real cost savings back to the business.

The need for change

While demands have changed and the power situation is gradually turning into a crisis, data center design practices haven’t changed much in decades. Today new and energy-efficient, greener technologies are available or are undergoing development in R&D labs. However, taking advantage of these developments requires that many existing concepts and practices in the construction and management of data centers be overthrown.

Satish Pendse, Chief Information Officer, Hindustan Construction Company said, “Cooling consumes around 35 to 40 percent of the electricity consumed in a data center; servers, storage, networking equipment, etc., also consume a considerable amount of power. Increasing redundancy from N to N+1 to N+2 also increases power consumption.”

Blade servers have many benefits and may seem to be a worthwhile proposition for many.

However, they can lead to densities for power and heat that existing facilities’ infrastructure cannot handle. Virtual PCs and other Thin Client architectures, on the other hand, can provide significant environmental advantages in system power consumption, reduced quantities of desktop equipment, and extended product lives. However, deployment requires a rethinking of overall IT system architecture for most enterprises. Virtualization and adoption of multi-core processors may also significantly affect the type and quantity of equipment to be installed in a data center.

Manikkam VS, Head-Information Technology, Henkel CAC explained, “Equipment densities are continuing to rise and it is important to have a roadmap for dealing with higher densities to ensure you are not limited in your ability to adopt new technology and make the most effective use of your data center space. Increasing rack spacing to accommodate higher densities is a costly strategy when facility costs are taken into account; significant savings can be achieved if the facility can scale to support higher density racks without reducing the number of racks being supported.”

Sometimes changing the placement of servers can help in avoiding heat issues, by converting a hot aisle into a cold aisle. That said, this is not always possible. Pendse explained that if one changes how servers face, one has to also change the path of power cabling, the network cables and the access approach to the servers. It may also happen that in an existing data center it will require some interior changes too, including changes to the floor, the heat vents. If you have a return ceiling plenum then that path needs to be changed or suitably modified to accommodate the hot aisle/cold aisle approach. This also may require downtime which may add to the cost but in the long run this is recovered through savings in the energy bill.

For facilities design, new technologies for liquid cooling at the rack level can address the heat removal requirements for high power, high density computing environments. Adopting these designs runs counter to the practice of data centers being designed as raised floor environments; a new cabling design and fresh management practices are needed. The use of industrial cooling technologies adapted from other industries is another area of innovation being offered for energy efficient cooling at the facility level.

“New technologies make it easier than ever to match cooling system capacity to current requirements, while easily adding capacity as needed,” Manikkam added. Newer floor mount precision cooling systems automatically adjust their capacity to room requirements without cycling compressors, increasing efficiency and reliability. This allows extra capacity to be designed into the system initially without a significant increase in energy costs.

For power efficiency, more efficient server power supplies are available today, as are new engineering approaches to eliminating inefficiencies in traditional systems with multiple AC/DC power conversions. Innovative designs for DC powered data centers that could radically increase power efficiency are being researched and tested.

A planned approach to green data centers

The cooling and power consumption requirements of a data center can be drastically reduced if proper planning is undertaken. It is good to plan for future requirements, but over provisioning everything also leads to inefficiencies creeping in.

James Mouton, Senior Vice-President and General Manager, Industry Standard Servers, HP Worldwide, said, “It’s important to assess your requirements before setting up a data center. Things like floor height, placement of servers and air- conditioners vary from case to case.” SMBs, he said, may not even require an entire data center in many cases. “For smaller requirements, an all-in-one box can serve the purpose of a data center, saving tons of money spent in setting up and maintaining it.”

Suresh Balakrishnan, Jt. Managing Director, STULZ –CHSPL stated, “Energy audits should be done on a regular basis to check if the existing equipment is up to date. This helps check any kind of inefficiency caused by the use of older equipment. Consultants should also be carefully chosen as many of them are not keeping up with changed demand in the design of a data center. Copying designs of a data center can turn disastrous in some situations.”

Balakrishnan pointed out that many vendors calculate capacity theoretically rather than calculating it practically. CIOs and IT managers should be careful about this and ask for a ‘Witness test’ to check the actual capacity of a cooling solution.

There are certain steps that IT managers cannot afford to miss. The following are the steps one should consider for optimum cooling and an energy-efficient data center:

• Sealing: You need to ensure that the data center is properly sealed to ensure optimum cooling. Otherwise the load on air-conditioners increases and correspondingly power consumption. It makes sense to cut off the data center environment from the rest of the building. Vapor sealing is a cost-effective solution and easy to implement. If the data center has raised flooring, then it is recommended to have the base flooring sealed with rubber or poly vinyl matting. Put sunscreens on windows, and if possible have two stage windows to trap air in between. The use of false ceilings is also advisable.
• Air flow: Air flow should be such that the maximum amount of heat is removed with minimal energy consumption. Conventional racks are designed to throw heated air from the rear. One can use the front facing racks and a conduit behind the rack that channels hot air upwards which is again sucked by the air-conditioner’s return path. The proper arrangement of cables behind racks also allows managing the air flow. Air travel should be minimized by placing air-conditioners at right angles to the hot air path (hot air being lighter travels upwards).
• Consolidation/optimization: Optimize by consolidating as much as possible. Virtualization can be used to consolidate servers/applications; use a quad processor server than two separate dual CPU machines (think of cost and simplicity before virtualizing). Use power management tools. Use the hardware to the maximum since the same power is consumed even if server is running at lower utilization levels.
• New technology: The use of technologies such as supplemental and embedded cooling should be adopted for more benefits. Supplemental cooling is a new approach that overcomes the limitations of raised flooring when rack density increases and embedded cooling can provide direct cooling to racks.

Be it a small, medium or large organization, energy saving means a lot to everyone, especially when it directly translates into heavy costs. That said, if appropriate measures are taken to ensure optimum efficiencies of data center equipment, every organization will be able to do its bit towards contributing to a greener earth.

varun.aggarwal@expressindia.com