After years of relying on the Amazon cloud to store its users' files, Dropbox has shifted gears and begun using primarily its own technology instead.

"We’re excited to announce that we’re now storing and serving over 90 percent of our users’ data on our custom-built infrastructure," the company said in a blog post Monday.

Dropbox stores two kinds of data: file content, and metadata about files and users. The service always had a hybrid architecture, whereby metadata was stored on Web servers in its own data centers while file content was stored on Amazon.

Growth prompted Dropbox to start building its own storage system back in 2013, leading to an initial launch in early 2015. By October, it had hit its goal of serving 90 percent of its data from its in-house infrastructure.

Performance and the need for customization were key motivators for the move.

"We knew we’d be building one of only a handful of exabyte-scale storage systems in the world," the company said. "It was clear to us from the beginning that we’d have to build everything from scratch, since there’s nothing in the open source community that’s proven to work reliably at our scale."

To provide the new storage, Dropbox leases space in several collocation facilities, including data centers in Ashburn, Virginia; San Jose, California; and Dallas. The company will continue to partner with Amazon when warranted, particularly globally. Later this year, it plans to expand its relationship with AWS to store data in Germany for European business customers.

For the most part, users shouldn't notice anything different as a result of the shift.

"Their files will sync with the same reliability as before across all of their devices, and as Dropbox adds more users, that performance standard should hold," said T.J. Keitt, a senior analyst with Forrester Research.

The bigger implications are strategic ones.

"The upstart cloud companies that have built their own global-scale infrastructure are Amazon, Facebook and Google -- companies that deal with billions of transactions and millions of users," Keitt said. "It seems that Dropbox feels that its arrow's pointed in that direction and it can't be constrained by someone else's infrastructure."

While Netflix has gone "all-in" with Amazon Web Services, Dropbox seems to believe that infrastructure isn't a utility or a commodity, he said. Rather, "they see it as a core enabler of their evolving ambitions to move past being an interesting file-synchronization system to a collaboration platform ready to compete with Google and Microsoft in both the consumer and enterprise arenas."

The move also flies in the face of many commonly held assumptions about the public cloud, including notions that it's "virtually always cheaper, easier and better for a company than owning and operating its own IT assets," said Charles King, principal analyst with Pund-IT.

"Though Dropbox is an extreme case in regards to the size and scope of its new storage infrastructure, it's not unique in recognizing the strategic and economic benefits of controlling its own IT destiny," King said.

Amazon did not immediately respond to a request for comment.