https://docs.openshift.com/container-platform/3.9/day_two_guide/environment_health_checks.html#day-two-guide-docker-storage
We should mention in our prerequisites that the file system of the partition should be xfs.
The updated documentation is available on the Customer Portal: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2-beta/html-single/metrics_store_installation_guide/#Prerequisites