This archive report was first published on 6 October 2021.
On October 4th, 2021, Facebook experienced a widespread outage that left its popular services, including the main Facebook app and service, Instagram, and WhatsApp, offline for hours.
The outage, which was later resolved, was attributed to DNS and BGP issues caused by a configuration change gone wrong by Facebook engineers.
"DNS is the address book of the internet, enabling the simple web names we type into browsers to be translated into specific server IP addresses," explained Facebook in a blog post.
As Facebook engineers worked to restore services, users turned to alternative platforms, with Telegram being a top choice. According to Telegram founder Pavel Durov, over 70 million people joined the service during the outage.
"The daily growth rate of Telegram exceeded the norm by an order of magnitude, and we welcomed over 70 million refugees from other platforms in one day," wrote Durov on his Telegram channel a day later.
As a result of the massive migration to Telegram, existing users experienced a degradation in service for a few hours. However, Durov praised his team's handling of the unprecedented growth, stating that Telegram continued to work flawlessly for the vast majority of users.
Unofficial reports also suggest that microblogging service Twitter benefitted from the outage, registering its highest number of users online at the same time ever.
