Keeping a lid on data center energy costs

MANILA, Philippines - Data center outages are a costly affair. In its February 2011 report “Calculating the Cost of Data Center Outages,” the Ponemon Institute estimated the average cost of an unplanned outage incident at about $505,500.

The institute, which surveyed senior managers at 41 data centers at least 2,500 square feet in size across varying industry segments in the United States, also found IT equipment failure to be the most expensive root cause of an outage.

Every CIO hopes that a data center outage does not happen under his watch but the reality is outages do occur.

In its study, the Ponemon Institute found that total outages occurred once a year on average and device-level outages occurred every two months.

An earlier study by market researcher Penn Schoen Berland found that roughly one-third of data centers experienced a power outage within the prior year.

Things can get pretty hairy when the power goes out in a data center. Initially, there is a short period during which racks still have access to the cold air in the aisles. Once this cold air is used up, the temperature starts to climb as the IT equipment heats up the still air and equipment within the room.

How fast this climb is depends on the volume and height of the data center, its design, and the power density of the equipment. It also depends on whether the air-conditioning chillers and air-handling blowers are backed up by uninterruptible power systems.

Still, even with UPS systems in place, servers and other IT equipment can reach critical temperatures during the shift to and from redundant power systems.

Riding through outages

When an outage does occur, what CIOs and their managers want most is adequate ride-through time, the amount of time the data center has to ride through a failure before the temperature reaches a critical level.

Once this temperature is reached, several things could happen: equipment could shut down automatically, performance could go down due to component or system throttling, or components or entire systems could degrade permanently.

Most IT systems have an operating maximum temperature of around 35 degrees Celsius and many hardware vendors void warranties for their products when this limit is reached.

Naturally, companies have invested heavily in cooling systems to keep their data centers well below this threshold. Most design their data centers to operate between 10 and 35 degrees Celsius with 80 percent relative humidity.

Cooling and air handling costs account for a significant portion of the energy consumption of a typical data center, with estimates in the 40-50 percent range. With electricity tariffs showing no signs of moving south and power density on the uptrend, CIOs are, well, getting hot under the collar and looking for alternatives to traditional cooling methods.

One of these alternatives is the chiller-less or fresh air approach. Used in recent data center deployments by companies such as Google, Facebook and Yahoo, it utilizes outside air to cool the air inside the data center.

However, the standard allowable temperature maximum of 35 degrees Celsius for today’s IT equipment limits the locations where the fresh air approach can be used without having to have a backup chiller for occasions when the temperature rises.

Dell Fresh Air

To enable the fresh air approach to be used in more locations and to meet the needs of a broader range of enterprises interested in employing more efficient and economical data center designs, Dell has validated a portfolio of its servers, storage, networking, and power infrastructure for sustained operation between -4 and 45 degrees Celsius and relative humidity from five to 90 percent.

The wider ranges are in line with the highest current temperature and humidity guidelines issued by the American Society of Heating, Refrigerating and Air-Conditioning Engineers.

However, fresh air cooling is not about running a data center at high temperatures 24x7 365 days a year. Rather, it is about the ability of data center equipment to tolerate a small number of short-term incidents of elevated temperature.

Tests have indicated that the validated Dell Fresh Air products can tolerate up to 900 hours of 40 degrees Celsius operation per year and up to 90 hours at 45 degrees Celsius, with limited impact on performance.

Dell has warrantied the products to these levels. The total Fresh Air ecosystem of products, with thermal, reliability and system engineering fully validated, is based on advanced thermal design and engineering; built-in thermal controls monitor the systems and adjust the fan speeds and frequency depending on the environment. The Fresh Air capability in the validated Dell products comes at no additional cost to the customers.

Wide benefits

Being able to run their IT equipment at up to 45 degrees Celsius for short periods gives enterprises a slew of benefits. Of these, the most significant is lower energy costs. Done over a portion of the year, those using Fresh Air-enabled solutions can see up to 50 percent savings on their electric bills.

For larger data centers, this equates to savings of upwards of $250,000 of cost avoidance per megawatt of IT.

Using the Dell Fresh Air ecosystem of products also increases data center efficiency and reduces maintenance/infrastructure costs while enabling enterprises to shrink their carbon footprint and stay ahead of government regulation.

In addition, the higher temperature tolerance reduces the risk of data loss and equipment failure in the event of cooling system failure, as well as provide more ride-through time to react appropriately and move into redundant operations such as performing a failover to a generator and restarting the chiller.

“Many enterprises are focused on driving much greater efficiencies in their data center operations. Dell Fresh Air technologies allow them to run hardware in the data center at extreme temperatures and humidity levels for short-term use and better leverage fresh air cooling, enabling them to enhance their productivity and data center stability while reducing capital and operating costs and being less demanding of the environment,” Christopher Papa, country manager of Dell Philippines, said.