Found at “Defcon: Preventing Overload with Graceful Feature Degradation” on 2024-03-01 11:01:38 +01:00.

To prevent overload from impacting its products, Meta developed a system called Defcon. Defcon provides a set of abstractions that allows incident responders to increase available capacity by turning off features, an idea called graceful feature degradation. By dividing product features into different levels of business criticality, Defcon also allows oncallers to take a variety actions depending on the severity of an ongoing incident.