The ACS documentation states that:
"Monitoring with Red Hat OpenShift is enabled by default. No configuration is required for this default behavior."
(Ref: https://docs.redhat.com/en/documentation/red_hat_advanced_cluster_security_for_kubernetes/4.8/html/configuring/monitor-acs#monitoring-custom-prometheus_monitor-acs )

The scope of this alert is currently limited, covering only persistent volumes in the openshift-, kube-, and default namespaces.

This non-coverage directly contradicts the messaging that monitoring is "enabled by default" and requires "No configuration," as a RHACS critical component is missed.

The central-db PVC (which is critical for ACS Central) typically resides in a custom namespace (e.g., stackrox or rhacs-operator), and is thus not covered by the out-of-the-box alerts for volume filling.