Facebook builds 'cold storage' archive for old photos

Facebook is building a vast new "cold storage" facility in the US to archive all the messages, photos and other postings that its over billion users do not need every day but want to retain for future reference.

A 16,000-square-foot data centre under construction in Prineville, Oregon, is designed to provide a more efficient home for older and less popular material.

The new cold storage facility will join two existing data centres in Prineville, The Oregonian reported.

Facebook knows you might want to see your old photos again someday. Or scroll back through your Timeline to revisit your posts as an online diary. But storing all those pictures and keeping them immediately available takes a lot of space.

Not in the physical sense, but in the virtual. That means lots of hard drives, lots of storage and lots of energy.

So Facebook is preparing to try out a more efficient storage system at its Prineville "cold storage", for those archival posts that people don't need every day, but that they don't want to lose altogether.

Facebook says 82 per cent of its traffic is focused on just 8 per cent of its photos. Its cold storage facility is designed to create a more efficient way to store those photos that are not in heavy rotation.

The cold storage building is just a skeletal frame now, and a concrete pad. Facebook hopes to have the first of three phases up and running soon.

Each of the three 16,000-square-foot data hubs could hold an exabyte of data, equivalent to 1 million hard drives inside a contemporary personal computer.

The tens of thousands of servers inside the two existing buildings are always on, ready to deliver your pictures and musings to your Facebook friends around the world.

By contrast, most of the computers in the new cold storage facility will be asleep. A few will be alert, awaiting a request for old material and ready to summon the slumbering computers to provide their data.

This material won't reach your computer as quickly as something posted just a few hours ago, but Facebook says it won't take long.

"The principle will be so that it doesn't impact the user experience, so think about a matter of seconds, or milliseconds," said Michael Kirkland, a Facebook communication manager.

Facebook estimates a cold-storage data center will cost one-third less than its standard data center.