Dropbox has been acquiring companies to help it expand the services that it can offer to consumers and enterprises beyond cloud storage. But the company — which has raised $1.1 billion and is among the larger tech startups tipped for an IPO — is also making strategic acquisitions to help keep its own house in order.

We have found out that Dropbox has quietly acquired a company called Parastructure, a startup still in stealth that builds data-analysis software on top of open source infrastructure.

TechCrunch has confirmed with a reliable source that the acquisition was in the “lower eight figures,” which could be anything from $10 million up to $50 million.

Neither company would confirm the deal to TechCrunch.

“Thanks for checking – we don’t have any comments however!” a spokesperson told me. Parastructure did not respond, and the startup took its site offline shortly after I started contacting the two co-founders, Salik Syed and Ryan Noon, asking questions.

A reliable source close to the company, however, confirmed that the acquisition is a “done deal” and also confirmed the general range of the price.

Update: Parastructure’s website now redirects to Dropbox.com. :-)

So what exactly is Parastructure? According to the company’s LinkedIn profile, and its (now-offline) home page, it builds “beautiful data analysis software powered by cutting-edge open source infrastructure.” Parastructure’s GitHub pages give some clues as to what that data-analysis software was tackling, with areas covering Spark for cluster computing; Phoenix, a SQL skin over HBase; CrunchBase; and so on.

“They had phenomenal business prospects going forward,” our source says. “They found a product-market fit and customers and were solving relational database problems no one else is tackling.”

Although Dropbox is making more moves to target the enterprise market, it seems that while Parastructure is an enterprise service, Dropbox is not intending to deploy it internally, and not as a product — not initially at least.

This may be one reason why Dropbox is keeping quiet: It simply shows the company’s hand too much. “Why tell potential competitors about what you are doing?” our source points out.

When you consider that the company has now passed 275 million users, is now managing both enterprise and consumer content and a host of services that move Dropbox beyond being a storage provider, and is looking to scale up even more, it’s no surprise that it’s beefing up its infrastructure with more database firepower for faster and more reliable performance.

Parastructure, based in San Francisco, has been around since 2012 with the co-founders both alums of Stanford.

The company didn’t make its list of backers very public. On LinkedIn it notes it is “venture funded and backed by several notable angel investors.” A look on AngelList shows that those investors include Amr Awadallah, the co-founder and CTO of Cloudera; other signs point to Accel also having been an investor in the company.