Energy Efficiency of Small Data Centers

October 23rd 2013
Example of a small data center

October-November Special Focus: Energy Efficiency, Buildings, and the Electric Grid

Fifty-seven percent of U.S. servers are housed in server closets, server rooms, and localized data centers, in what are commonly referred to as small server rooms, which comprise 99.3 percent of all server spaces in the U.S. While many mid-tier and enterprise-class data centers are owned by large corporations that consider energy efficiency a goal to minimize business operating costs, small server rooms typically are not similarly motivated. They are characterized by decentralized ownership and management, and come in many configurations, which creates a unique set of efficiency challenges.

To develop energy efficiency strategies for these spaces, we surveyed 30 small server rooms across eight institutions, and then selected four of them for detailed assessments including some power measurements. This revealed Power Usage Effectiveness (PUE) values ranging from 1.5 to 2.1. Energy saving opportunities ranged from no to low-cost measures such as raising cooling set points and better airflow management, to more involved but cost-effective measures including server consolidation and virtualization, and dedicated cooling with economizers.

We found that inefficiencies mainly resulted from organizational rather than technical issues. Because of the inherent space and resource limitation, the most effective measure is to operate servers through energy-efficient cloud-based services or well-managed larger data centers rather than server rooms. Otherwise, backup power requirement, and IT and cooling efficiency should be evaluated to minimize energy waste in the server space. Utility programs are instrumental in raising awareness and spreading technical knowledge on server operation, and the implementation of energy efficiency measures in small server rooms.

Iris Cheung