Metrics and key performance indicators (KPIs) for data centers used to be inward looking. In the not so distant past, KPIs tended to be “about the box,” measuring factors like server utilization.
Information technology (IT) managers steadily realized there was more to data centers than utilization, or even uptime. In particular, quality of service to business users grew in importance. As a result, we began to see metrics in areas like query and transaction response times, or with IT help desk, job ticket turnaround.
In recent years, the energy costs of data centers came into focus. In a 2007 report to Congress, the Environmental Protection Agency figured thatU.S. data centers consumed about 61 billion kilowatt-hours (kWh) in 2006, about as much energy as used by 5.8 millionU.S. households. It also predicted that by 2011, energy use inU.S. data centers would exceed 100 billion kWh, or $7.4 billion in annual cost.
As highlighted in the white paper 154, “Electrical Efficiency Measurement for Data Centers,” a 1 MW high availability data center can consume $20 million in electricity over its lifespan. What can be done to minimize such huge spend levels? Well, we know it’s not just IT hardware consuming electricity. As the paper points out, the power and cooling infrastructure in a typical installation can consume half the electricity.
This realization has elevated the importance of the Power Usage Effectiveness (PUE) metric as a way to measure the efficiency of a data center’s physical infrastructure. PUE has become one of the most vital data center metrics. If managers measure PUE effectively, they have a great tool for ensuring energy is spent where it matters most, but there also is the danger of getting overly hung up on one metric.
The best approach is more holistic, taking a step back to consider bigger objectives, including:
In other areas of business, the need to think more broadly about metrics and link them with strategy is seen in methods such as The Balanced Scorecard, which combines financial and non-financial measures to better gauge corporate performance. Similarly, data center managers need the right mix of metrics.
As Kevin Brown notes in a recent blog post, we risk becoming “metric zombies” if we assess a metric like PUE in a ***, irrespective of projects like data center consolidations that might temporarily harm PUE, but whose achievement is necessary to keep budgetary mandates on track. In short, think first about the whole range of metrics and drill downs you want in a dashboard—not just one number.