Private-equity firms have committed a total of US$20.5m in growth capital to two US data center services companies focused on Infrastructure-as-a-Service in two separate deals announced earlier this week.

Plano, Texas-based Vazata secured $13m from Altpoint Capital Partners, Ballast Point Ventures and its own CEO Lance Black, while Denver-based PeakColo got a $7.5m infusion from Meritage Funds and Sweetwater Capital.

The news is a sign of confidence by the private-equity community that there is enough room in the IaaS market for companies other than the incumbent leaders like the behemoth Amazon Web Services, or smaller but well-known providers like Rackspace and Savvis.

This confidence is despite recent entry into the market for providing on-demand virtual compute resources of two companies whose size and infrastructure chops put them in the position to compete with Amazon directly: Microsoft and Google.

Paul Johan, partner at Ballast (one of the investors in Vazata), said “US market growth projections for cloud services and IaaS are significant. We view this as a critical step in the process of not only expanding Vazata’s market presence in terms of solution offering and customer portfolio, but also in accelerating Vazata’s growth rate.”

Gartner analyst Lydia Leong wrote in a recent blog post that growth in the IaaS market was “huge, but is disproportionately concentrated on a modest number of vendors.” Amazon is so far ahead of everybody else that measuring others in the space against the cloud giant is a useless exercise.

“The data suggests that to succeed in this market, you have two possible routes — you have a giant sales channel with a ton of feet on the street and existing relationships, or you have excellent online marketing and instant online sign-ups,” she wrote.

“A third possible route is that you make it easy for people to white-label and resell your service.” This is a major part of PeakColo’s strategy.

The Denver company provides “white-label” cloud services to its distribution, data-center, service-provider, system-integrator and value-added-reseller channel partners.

Vazata (formerly known as Horizon) has a major focus on the federal cloud market, although it also touts success in Software-as-a-Service-provider, sports and entertainment, healthcare, legal and other industry verticals.