The data traffic between all these computing facilities is managed by routers, which figure out where to send all the incoming and outgoing data.
During one of these routine maintenance jobs, a command was issued with the intention to assess the availability of global backbone capacity, which unintentionally took down all the connections in our backbone network, effectively disconnecting Facebook data centers globally.
Once our backbone network connectivity was restored across our data center regions, everything came back up with it.
[Via]
