Toward a Greener DataCenter

Data center managers see the 'green' escalating IN their 'to do' list. it is also shooting up in the list of vendor differentiation strategies. It is high time for us to capture this trend, which tends to assimilate more environment-friendly data center Behavior

Wednesday, September 05, 2007

It was on my hit list for quite a while and I have been closely watching this positive trend of growing affinity for 'green', from both sides, be it users or manufacturers of data center equipment. But, when my protagonist, Mr Amitabh Bachchan, propagated the message of Global Cool, at the recently held IIFA awards ceremony, in the picturesque county of Yorkshire in northern England, I could not resist the idea of a green story. While Global Cool talks of eco-homes, green fuels in airlines, etc, our agenda is data centers.

The impulsion
Ever since the days of Industrial Revolution or may be earlier, we have been hearing horror stories of how mankind will suffer from overuse of technology. That our natural resources will quickly deplete causing an 'immediate' threat to us. Oil wars further fueled the stories around oil crisis. Later on, we heard of the greenhouse effect, ozone layer depletion, global warming, etc. We've been hearing all this for ages. The general thought process is that it's an old tussle and will continue. 'No, the sky is not falling', then why should one bother? If there will be no electricity or no oil, there will be something to source up my car or for that matter, even my data center. Scientists are already working on renewable and other sources of energy. They will find a way out, so there's no need to worry. We have plenty of time. BUT, do you really know 'how much time'? Unfortunately not, and it's because of this very reason that most people end up becoming complacent and don't bother about energy saving. But if you really look at it, then this is also the very reason you must start planning for it right now. Most data centers around the world have started becoming more energy efficient and what's more, they're even reaping business benefits out of it. It will not be long before one starts seeing a similar trend in India as well. There's enough buzz and concern in the market around energy consumption to drive it through. It therefore makes sense to start planning for it, immediately, so that you don't lag behind.

Why have green data centers?
In data centers, it used to be the floor space that was at premium, but lately power availability has started to appear as a bigger concern. The reason is simple. As your business grows, you keep adding more servers, storage, networking, and other equipment in your data center. Then, in order to keep them all running, you add more power management devices, and finally, add more air conditioning to keep them cool. Before you know it, your power consumption shoots through the roof, and so do your electricity bills. This is a cost you can't avoid, but can definitely reduce considerably through proper planning and using more energy efficient devices. This of course, is easier said than done, but you need to make a start, anyways. And, who knows that may qualify you for some tax benefits, electricity rebates or some other governmental incentives to come in future!

Core of the problem
Since the days of yore, electrical usage was not considered as a considerable design criterion for data centers and also, as it was incurred, was not effectively managed as a data center expense. As a matter of fact, people managing data centers hardly had an idea of how much electricity was being consumed by their data center every month and who were the main culprits that consume more power than what they should. And, to make the situation worse, there were no proper guidelines and standards, as to what was permissible limit for a particular piece of equipment. Sometimes, the equation would become so bad that the cost of electricity over the life of a data center became more than the costs of the power system and the UPS, or even more than the cost of servers and storage.

Inventor Jay Harman of Pax Scientific has designed an energy efficient fan. He found the inspiration in the spiral flow patterns of water and air

It was hard to establish a correlation between particular decisions and their impact on the electricity consumption. For example, it was difficult to figure out the electrical usage implications of the installation of a new zone of equipment in the data center or of a new operational practice. Tools for simulating the electrical costs of data centers were neither widely available nor very accurate and usable, offering little motivation for getting used during data center designing.

It was also difficult to find the electrical costs of a decision, as the electricity bills were sent out long after the actual charges were incurred. The bills would normally land in a department, which had little or no connection with data center administration. Even if you got to see the bills, it was difficult to cull out the actual expense made by the data center, during a particular course of time, as normally, you didn't get to have the separate bill for the data center entity.

If the things are still like this at your data center, please make up for those and involve the top management to change the situation for better. It's wise to be informed, while making policy decisions. And, in case of data center it becomes more detrimental, as a wrong decision may cost you a limb.

At the core, there are also system design issues that commonly reduce the electrical efficiency of a data center. Generally, power distribution units are found not utilizing their full capacities. Air conditioners are forced to drive air over long distances, requiring them to consume more power. Cooling pumps that use valves to automatically adjust their flow rate, usually accrue more power than the ones that need manual intervention.

You must know how much redundancy you want in the system. N+1 or 2N redundant designs are fine, but they result into under-utilization of components, so better guard against too much of redundancy. Too much of oversizing of UPS should also be avoided, unless it is operating very near its capacity limit. Also, if you continuously run your UPS at low loads, it may affect its actual efficiency in the long run.

Where to save energy?
Ideally, energy improvements should start from the point where data center floor is being designed. The planning of equipment should be done with a view of energy saving.

The hot air is directly sucked up from within the racks through closely mounted ducts instead of being thrown out into an aisle. Only cold air remains in the aisles

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