Update https://docs.openshift.com/container-platform/4.14/monitoring/configuring-the-monitoring-stack.html#modifying-retention-time-and-size-for-prometheus-metrics-data_configuring-the-monitoring-stack to clarify that because data compaction occurs only every two hours, if the persistent volume fills up too quickly before this compaction occurs, the space on the persistent volume might exceed the retention limit. If this occurs, the KubePersistentVolumeFillingUp alert will fire until the space on the persistent volume is lower than the retention limit. Probably could add this information in a Note admonition in the bulleted list.