Facebook, WhatsApp, Instagram, Oculus Outage

Trace the October 4, 2021 outage from a backbone command to unreachable DNS and impaired recovery tools. The case shows how safeguards and recovery paths can share the dependency they are intended to protect.

On October 4, 2021, Facebook and related services experienced a global outage lasting roughly six hours. Facebook’s engineering report describes the technical chain and recovery. This lesson focuses on that evidence rather than unverified revenue-loss estimates.

The sequence of events

A chain reaction of technical failures led to the total blackout: