What initiates alerting for error rates in Dynatrace?

The initiation of alerting for error rates in Dynatrace is tied to the application reaching a certain level of activity, indicated by the statement that "begins when the application has run for at least 20% of a week." This represents a threshold where enough data is collected to assess application performance reliably. In monitoring systems, particularly ones focused on real-time data analysis, having a significant amount of activity is essential to create meaningful and accurate alerts. Monitoring an application without a substantial amount of traffic or activity could lead to misleading interpretations of error rates or performance issues.

The other options reflect scenarios that do not set a solid foundation for alerting. For instance, an application being idle for a period would not provide adequate data to gauge performance or error rates. Similarly, awaiting a particular percentage of a week's activity before beginning alerting captures the idea that consistent operations allow for the analysis needed to determine failure states effectively. Alerting systems like Dynatrace are designed to minimize noise and false positives by only triggering under conditions where sufficient context has been established.