On a knife Edge

Data centers are beginning to feel the heat, so it is essential that they are able to utilize power more efficiently. James Hall, President of the Blade Systems Alliance, argues that blade servers are just one option for data centers looking to optimize performance.

As data centers grow at an exponential rate, data center managers are faced with a worrying dilemma – how to house ever-increasing electronic resources whilst reducing energy consumption and waste. According to IDC, servers that consumed an average of 100 watts of power 10 years ago now consume an average of 400 watts. The bad news is that the number of servers are growing at an alarming rate – 10 years ago there were about six million, now there are 24 million with the number expected to increase to 35 million in 2010. The result, unless action is taken, is that power consumption is likely to reach colossal levels.

Reducing consumption is a tricky but necessary requirement, with some centers requiring 40-50 times more power than an office of the same size. It’s no surprise, therefore, that reducing energy consumption is high on the agenda of many organizations. The problem is so great in some states that power companies are offering financial incentives to companies to virtualize servers.

However, reducing energy use is perfectly achievable and there are a number of things data center managers can do. “In particular they can look at underutilized servers and inefficient server power supplies,” suggests James Hall of the Blade Server Alliance. “Using servers with the most efficient power supplies is really important. Server power supplies are now available at about 90 percent efficiency. Getting this right has the potential to make a big impact on your data center energy expenditure. You’ll also want to look at how much power is being used when idling, and consider virtualization to effectively use what you’ve got.”

Virtual reality
The underutilization of servers is a common challenge in the data center environment but is a problem that can be mitigated. In many cases, servers are running all the time, but only at 15-20 percent of their useful capacity. “If you could take the capacity of your server and increase the utilization to a much higher factor (80-90 percent) without adding any additional capacity (servers, blade servers, etc.), then you could have a dramatic impact on your ability to handle computing loads and requirements by virtualizing your environment,” he explains. “This means that if your servers are handling multiple rather than just single applications, then you can multiply the applications using the same equipment. Traditionally, you have only one application running on a server. If that server is running multiple applications, then this is part of the virtualization process. Huge increases in capacity can take place just by utilizing what you already have. Blades are a great vehicle for virtualizing. Computing capacities vary across different applications, whereas the computing capacity of a blade is rarely an issue.”

Cooling systems are another essential aspect of a data center, ensuring that equipment does not overheat and malfunction. Unfortunately, these can be expensive to run and can use a lot of energy; in fact, about 30-40 percent of the energy used by the data center goes straight towards cooling. Running efficient equipment is therefore crucial, advises Hall. “There is a significant opportunity to save energy in the data center by paying attention to what you’re doing with your cooling approach,” he says. “There are a number of new ways to rearrange the data center. For example, hot aisle/cold aisle arrangement. ASHRAE has put together standards that cover using the hot aisle/cold aisle for rack arrangements to help deal with cooling issues.”

Taking measures to ensure equipment is in good order can also be beneficial. Hall recommends the importance of ensuring vapor seals are in place to avoid condensation in the data center: “It seems like a small thing, but you have to make sure that you have tight data center when you are trying to improve cooling efficiency.”

Another measure he suggests is to make sure you have a way of removing the heat generated by the power being used inside the data center. “Your base-level precision air conditioning should operate efficiently at levels below peak load, since peak design load is rarely ever reached. Also, by moving your cooling closer to the source of heat, you’ll minimize the fan power needed to move the air.”

Going green
Many would questions whether a data center can ever be considered ‘green’ given the amount of power it takes to keep one running. However, there are steps organizations can take to help make their center more environmentally friendly. “For example, you can locate your data center in a place where free air is used,” suggests Hall. “It is possible to mitigate some of the things that are happening by having cooling ponds close by and trees that create shade. These give you the ability to reduce the amount of heat that exists. It’s important to be smart when considering where to locate your building. Your power source doesn’t need to be a utility. It could just as easily be a co-generation site where you can use alternate energy like solar, wind, hydro or thermo.” For instance, the availability of cheap hydroelectric was a strong factor when Google and Microsoft decided to build new data centers in Washington State.

Even measures such as peak shaving can have a marked effect on power output. Utilizing power at times in the day when rates are lower can have an effect on rates from anywhere between 10-30 percent. It is essential to monitor and manage utility power consumption.

Blades versus racks
As IT managers strive to improve efficiency, it is no surprise that blades are the fastest-growing segment of the market with revenue in 2006 growing by over 36.5 percent. Not only do they offer more memory, they also reduce waste and take up less space. Blades fit into a chassis, which have a typical capacity of 14 or 16 blades. If a company uses a lot of servers then choosing blade over rack servers is likely to make more economic sense. Provided that the customer buys enough servers to fill half the chassis, then the cost of blades should break even with the cost of rack-mounted servers. Another benefit of blades is that companies don’t have to buy much additional equipment, as chassis already include the components needed for cabling, switching, networking and power supplies.

Despite the benefits, data center managers still have misgivings about investing in the technology. In a recent survey by TechTarget, 30 percent of the respondents said that cooling issues put them off investing in blades. A further 27 percent cited the cost of chassis as too high, whilst 22 percent considered the technology inappropriate for organizational workloads. Hall thinks a lack of understanding might be to blame for the reluctance of some companies to invest: “There is still a lot of misunderstanding within the user community about what’s practical and available,” says Hall. “The end-user is faced with a plethora of different information. With blade technology, I’m sure there are many who think it is too hard to manage and they might not be able to cope. The outcome is that people are concerned when considering implementing these kinds of technologies.”

Careful planning is recommended before implementing blades to ensure that the company is able to cope with a high-density blade server environment. One essential consideration is to ensure that a proper cooling system is in place to prevent overheating, as blade servers can produce more heat – for instance, 10 blades may throw out 20 percent more heat in the same amount of floor space than traditional servers.

Continued demand
As environmentally friendly practices become more of a concern for organizations, smaller, better designed, more efficient and less wasteful data centers will likely take center stage. The demand for more computing capacity is set to increase over the next few years and, as a result, manufacturers will be ensuring they are capable of meeting customer needs. “These demands will continue to increase at an exponential rate and the server manufacturers will answer that demand,” predicts Hall. “If the demand is there for the product then there are many capable manufacturers that can support it. Assuming demand rates continue to rise for high-density servers, support systems will continue to evolve.”