GitHub issue:

https://github.com/openshift/openshift-docs/issues/49528 

Which section(s) is the issue in?

https://docs.openshift.com/container-platform/4.10/monitoring/configuring-the-monitoring-stack.html#persistent-storage-prerequisites

What needs fixing?

Current: Because Prometheus has two replicas and Alertmanager has three replicas, you need five PVs to support the entire monitoring stack.

Should be updated to: Because Prometheus has two replicas and Alertmanager has two replicas, you need four PVs to support the entire monitoring stack.

Reason: Starting with OCP 4.10 there are only two replicas of Alertmanager

Same change will be required for OCP 4.11 branch too.