Last month, Facebook created "Look Back" videos for its users as way to celebrate 10 years of the social network, and on Thursday, the company said that more than 720 million videos were created.
The Menlo Park tech giant released a blog explaining the engineering behind the massive project. Facebook said the "Look Back" videos were a last-second project that staffers volunteered to work on and had less than one month to complete. Each video showed users a recap of their time on the social network.
"Only a handful people at Facebook knew of the concept, and we had only a faint idea of how we would make more than a billion videos in 25 days," the company said.
To ensure the company could handle creating the videos without disrupting the social network's normal functions, Facebook estimated that it would need as many as 25 petabytes of disk space. One petabyte is equal to about 1,000 terabytes, or 1,000,000 gigabytes.
Fortunately, Facebook found a way to optimize video size without reducing quality, and in the end, the company ended up using only 11 petabytes.
Once the videos were made available on the company's 10th birthday, Feb. 4, users quickly began sharing them. At its peak, Facebook saw its outgoing traffic go up 20% more than normal, or reach levels of 450 gigabits per second.
"Which is big even by Facebook standards," the company said.
The company said it had estimated that 10% of users who saw their videos would share them. But the feature proved popular, and ultimately, 40% of users who saw the videos shared their own.
"The Look Back project represented the things we love about Facebook culture: coming up with bold ideas, moving fast to make them real, and helping hundreds of millions of people connect with those who are important to them," the company said in its blog. "Happy birthday, Facebook!"