"Degraded performance" means degraded performance, i.e. the system is not as performant as usual, probably manifesting as high API latencies and/or a significan

"Degraded performance" means degraded performance, i.e. the system is not as performant as usual, probably manifesting as high API latencies and/or a significant failure rate in the case of some public-facing "cloud" service. If certain functions of the service are completely unresponsive, i.e. close to 100% failure rate, that's not "degraded performance"---it's a service outage.