diff --git a/datacenter/ucp/2.2/guides/admin/monitor-and-troubleshoot/index.md b/datacenter/ucp/2.2/guides/admin/monitor-and-troubleshoot/index.md
index 6fc18596ce..1e270638e3 100644
--- a/datacenter/ucp/2.2/guides/admin/monitor-and-troubleshoot/index.md
+++ b/datacenter/ucp/2.2/guides/admin/monitor-and-troubleshoot/index.md
@@ -64,6 +64,10 @@ URL of a manager node, and not a load balancer. In addition, pinging the
 endpoint with a `HEAD` results in a 404 error code. Use a `GET` request instead.
 
 
+## Monitoring disk usage
+
+Web UI disk usage metrics, including free space, only reflect the Docker managed portion of the filesystem: `/var/lib/docker`.  To monitor the total space available on each filesystem of a UCP worker or manager, you must deploy a monitoring solution, such as  Prometheus Node Exporter.
+
 
 ## Where to go next