Dropbox bought Cove to help it grow like Facebook

Drew Houston

With more than 45 million users already connected to his company’s cloud storage service, Dropbox CEO Drew Houston knows he has an infrastructure challenge ahead of him. The challenge is that as Dropbox adds users and devices, it approaches the echelon of web companies that includes heavyweights such as Facebook and Twitter. And as they’ve shown us time and time again over the past few years, there comes a time when you have to go big on infrastructure or go home.

That, Houston told me, is a big reason Dropbox bought collaboration startup Cove, the founders of which played major roles in building out some of Facebook’s big features while they were there, from 2005 through 2010.

Right now, Houston said Dropbox relies on Amazon Web Services (s amzn) for storing users’ files, but it also manages its own 1,200-plus server infrastructure that handles pretty much everything else. Dropbox also built its own file system that Houston says has to be one of the biggest around in terms of sheer scale. It has done this with just “a few dozen” engineers split across about seven or eight subteams, and only about six people dedicated to the backend infrastructure.

“Find smaller numbers of really amazing people, and you can accomplish a lot more than you might think,” Houston said about his lean engineering team.

But the company aspires to be on par with Facebook and other web leaders in terms of building out advanced web infrastructure, and that’s where the Cove team comes in. Not only does it give Dropbox some of the additional staff it will need to focus on infrastructure, it also gives Dropbox some great staff. After all, as Houston said, “There’s only so many people in the world who think big and want to have a big impact and also have built a product that has touched hundreds of millions of people.”

Cove Co-Founder Aditya Agarwal told me Cove is in the process of building its own backend infrastructure that aligns quite nicely with some of what Dropbox wants to do. Going forward, the plan is to integrate a large portion of the Cove and Dropbox systems, but there are some clear areas of integration early on, including around Cove’s search index.

One thing that probably won’t happen, Houston said, is a move away from Amazon S3 (s amzn) for storing file data. Other large web companies, such as Zynga (s znga), like to save money by moving cloud computing workloads back in-house once they reach a certain size and predictability, but Houston said AWS provides too much functionality and flexibility to consider abandoning it right now.

Ultimately, Houston said, Dropbox is more than just an app on an iPhone (s aapl); it’s trying to build a fabric that ties together every service, device and app. Forty-five million users means even more connected devices — possibly hundreds of millions — and those numbers are only growing. “[C]onnecting all of that,” Houston said, “is a massive engineering challenge.”