Two billion photos are shared daily on Facebook services. Many of these photos are important memories for the people on Facebook and it's our challenge to ensure we can preserve those memories as long as people want us to in a way that's as sustainable and efficient as possible. As the number of photos continued to grow each month, we saw an opportunity to achieve significant efficiencies in how we store and serve this content and decided to run with it. The goal was to make sure your #tbt photos from years past were just as accessible as the latest popular cat meme but took up less storage space and used less power. The older, and thus less popular, photos could be stored with a lower replication factor but only if we were able to keep an additional, highly durable copy somewhere else.
Instead of trying to utilize an existing solution — like massive tape libraries — to fit our use case, we challenged ourselves to revisit the entire stack top to bottom. We're lucky at Facebook — we're empowered to rethink existing systems and create new solutions to technological problems. With the freedom to build an end-to-end system entirely optimized for us, we decided to reimagine the conventional data center building itself, as well as the hardware and software within it. The result was a new storage-based data center built literally from the ground up, with servers that power on as needed, managed by intelligent software that constantly verifies and rebalances data to optimize durability. Two of these cold storage facilities have opened within the past year, as part of our data centers in Prineville, Oregon, and Forest City, North Carolina.