ClearSky Data Inc. said today it has raised $20 million in venture financing and signed a partnership with colocation provider Equinix Inc. that will expand its footprint across the U.S. and eventually internationally.

ClearSky sells a storage-as-a-service platform that provides guaranteed performance and data protection across a global network by using colocated equipment and a proprietary caching technology that continually categorizes data and places it in the most appropriate location based on usage patterns and customer policies.

The company said it’s growing rapidly, with first-half revenue more than eclipsing sales for all of 2017. ClearSky started as a pure storage provider but has recently added disaster recovery and compute on-demand features. “You can’t solve part of the customer’s problem. You have to solve it completely,” Chief Executive Ellen Rubin (pictured) said of the decision to expand into the virtual server business.

Based in Boston, ClearSky has primarily focused on east coast companies but will be expanding nationally over the next 12 months with the addition of eight new locations that include Texas and the San Francisco Bay Area. It expects to add its first international locations beginning in 2020. Equinix operates 200 colocation facilities on five continents and claims 99.9999 percent global uptime.

“A lot of the work we’ve been doing has been proving out the technology,” Rubin said. “This funding is more about adding sales and marketing resources. We want to show customers how quickly we can expand.” Rubin characterized the funding as a “strategic round,” and said the company will probably seek one more capital infusion before expanding internationally. “At that point we’ll be break-even,” she said.

This round included new investor Pear Tree Partners L.P. and an unnamed “very large, very well-known tech company,” Rubin said. Existing investors General Catalyst Partners LLC, Highland Capital Partners and Polaris Partners LP also participated.

ClearSky launched with funding from Akamai Technologies Inc. which did not participate in this round. The company has now raised $59 million since its 2014 founding.

“Enterprises want to be able to run their apps anywhere — on-premises, in the cloud or at the edge — and still access their data rapidly and on-demand,” Dave Barrett, managing partner at Polaris Partners, said in a prepared statement.

The deal is important for ClearSky because its service depends upon proximity to customer location. The company deploys a combination of on-premises and colocation in cloud services to optimize performance and availability. The most critical data is cached at the edge in flash storage. So-called “warm data” is cached in a ClearSky point of presence location within 120 miles, and all data is stored in multiple locations in the public cloud.

Photo: ClearSky