"We think a software approach is more sustainable because it's more lightweight," Oberoi said.

EnergyCenter 2.0 is sold on a subscription basis for $500 per server rack per year, or as a perpetual license for about $1,500 per rack, Oberoi said.

The company has "north of 20" customers and expects to add eight more in the coming months, Oberoi said. Its customers are mostly large enterprises in North America, but Viridity is working with a distributor in the U.K. and plans to enter Germany and Japan as well.

Interest in DCIM tools is being driven in Europe by cap and trade laws that require companies to report their energy usage, and in the U.S. by growing awareness of the high cost of data center power and cooling, Oberoi said. In Japan, data centers have been told to cut their energy use 20 percent because of the ongoing nuclear power crisis there, he said.