US federal CIO Steven VanRoekel and associate administrator of the General Services Administration David McClure had to explain the “sudden” doubling in the number of data centers in government agencies' inventories to a government oversight committee Thursday.

An operations subcommittee of the House Committee on Oversight and Government Reform wanted to know why the inventory went from about 3,100 data centers reported in 2011 to about 6,800 in July 2013.

The reason, McClure said, was a change in definition. The Federal Data Center Consolidation Initiative did not initially consider any room smaller than 500 sq ft to be a data center.

Eventually, the Office of Management and Budget (OMB), one of the agencies overseeing the consolidation program, realized that this definition missed a lot of IT infrastructure assets and changed it.

“While this has created challenges in defining the government-wide inventory baseline, it provides a far more accurate view of each agency's enterprise assets and enables more comprehensive portfolio analysis,” he said.

Inventory data the OBM has received so far has indicated that more than 70% of agency data center assets were in sub-500-sq-ft rooms, many of them even smaller than 100 sq ft.

The definition of a data center used by the initiative since March 2012 has been “a closet, room, floor or building for the storage, management and dissemination of data and information.” Such a room houses computer systems, redundant power supplies and network-connectivity equipment, as well as having environmental controls under the current definition.

The GSA manages logistics for the consolidation initiative. It collects information from agencies, checks for completeness of the information submitted and provides tools for agencies to use in their consolidation activities.

One of the tools the administration has created is a central repository of data on the consolidation initiative. Each agency is responsible for uploading its inventory and closure data to the online Inventory Portal and must update it quarterly.

The portal, McClure said, “provides portfolio-level transparency, enabling analysis and planning, both by agency managers and OMB (Office of Management and Budget).”

McClure made sure to point out that the GSA is not responsible for verifying whether the information agencies submit on their data center footprint is accurate. That responsibility is on each individual agency's CIO's shoulders.

McClure also explained to the subcommittee that the consolidation initiative has changed focus from measuring success by the number of data centers to measuring efficiency in the context of overall IT portfolios. As part of this changed focus, agencies are now required to make plans to consolidate infrastructure into core data centers, while closing non-core ones.