diff --git a/nixos/modules/monitoring/server/grafana-dashboards/resources-overview.json b/nixos/modules/monitoring/server/grafana-dashboards/resources-overview.json
index 6eeeb226fd7d68e167ea59d3a0883c2438d728d4..130639b18c1242f4306d2baf5caaadaadc5b7855 100644
--- a/nixos/modules/monitoring/server/grafana-dashboards/resources-overview.json
+++ b/nixos/modules/monitoring/server/grafana-dashboards/resources-overview.json
@@ -375,11 +375,26 @@
             "uid": "000000001"
           },
           "exemplar": true,
-          "expr": "1 - (node_memory_MemAvailable_bytes + node_zfs_arc_size) / node_memory_MemTotal_bytes",
+          "expr": "1 - node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes unless node_zfs_arc_size",
+          "hide": false,
+          "instant": false,
           "interval": "",
           "intervalFactor": 4,
           "legendFormat": "{{instance}}",
-          "refId": "A"
+          "refId": "Hosts without ZFS"
+        },
+        {
+          "datasource": {
+            "type": "prometheus",
+            "uid": "000000001"
+          },
+          "exemplar": true,
+          "expr": "1 - (node_memory_MemAvailable_bytes + node_zfs_arc_size) / node_memory_MemTotal_bytes",
+          "hide": false,
+          "instant": false,
+          "interval": "",
+          "legendFormat": "{{instance}}",
+          "refId": "Hosts with ZFS"
         }
       ],
       "title": "RAM used %",