How Facebook launched ‘Look Back’ videos without breaking Facebook

Every now and then, it’s good to be reminded how something so mundane as a new Facebook (s fb) feature can actually be a daunting technological task or a noteworthy achievement. The one-minute Look Back videos the company let users build as part of its 10th anniversary festivities appear to be such a case, according to a Thursday morning blog post.

In less than a month, the authors explained, Facebook had to assemble the infrastructure to handle what it initially assumed would be 25 petabytes worth of storage and 187 gigabits per second of peak bandwidth. However, getting enough storage and network capacity wasn’t even the hardest part. The biggest challenge might actually have been monitoring power consumption to ensure that rendering hundreds of millions of relatively large video files and having an estimated 25 million people sharing them on the first day alone wouldn’t suck too much of the power Facebook allocated to its data centers.

The blog post goes into a lot more detail, but the results are impressive:

  • Over 720 million videos rendered, with 9 million videos rendered per hour
  • More than 11 petabytes of storage used
  • More than 450 Gbps outgoing bandwidth at peak and 4 PB egress within days
  • Over 200 million people watched their Look Back movie in the first two days, and more than 50% have shared their movie.

That’s a lot of storage, a lot of computing and a lot of packets sent over the network — all for something I hadn’t even heard of until reading about how hard it was to make it happen.