diff --git a/mon-system/prometheus-rules.yaml b/mon-system/prometheus-rules.yaml
new file mode 100644
index 0000000..262c9dd
--- /dev/null
+++ b/mon-system/prometheus-rules.yaml
@@ -0,0 +1,73 @@
+# =============================================================================
+# Prometheus Alerting Rules for Longhorn
+# =============================================================================
+
+# =============================================================================
+# Prometheus Alerting Rules for Longhorn
+# Excludes prometheus-data PVC since it's designed to run at ~95% capacity
+# =============================================================================
+
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: prometheus-rules
+  namespace: mon-system
+  labels:
+    app: prometheus
+data:
+  longhorn-alerts.yml: |
+    groups:
+      - name: longhorn-volume-alerts
+        rules:
+          # Critical: Volume at 95% capacity (excluding prometheus-data)
+          - alert: LonghornVolumeSpaceCritical
+            expr: |
+              (
+                (avg by (volume) (longhorn_volume_actual_size_bytes{volume!="pvc-6c6f1864-de15-4f10-9d73-8fbb678c391f"}))
+                / 
+                (avg by (volume) (longhorn_volume_capacity_bytes{volume!="pvc-6c6f1864-de15-4f10-9d73-8fbb678c391f"}))
+              ) * 100 > 95
+            for: 5m
+            labels:
+              severity: critical
+            annotations:
+              summary: "Longhorn volume {{ $labels.volume }} is critically full"
+              description: "Volume {{ $labels.volume }} is at {{ printf \"%.1f\" $value }}% capacity. Immediate action required."
+          # Warning: Volume at 85% capacity (excluding prometheus-data)  
+          - alert: LonghornVolumeSpaceWarning
+            expr: |
+              (
+                (avg by (volume) (longhorn_volume_actual_size_bytes{volume!="pvc-6c6f1864-de15-4f10-9d73-8fbb678c391f"}))
+                / 
+                (avg by (volume) (longhorn_volume_capacity_bytes{volume!="pvc-6c6f1864-de15-4f10-9d73-8fbb678c391f"}))
+              ) * 100 > 85
+            for: 10m
+            labels:
+              severity: warning
+            annotations:
+              summary: "Longhorn volume {{ $labels.volume }} is running low on space"
+              description: "Volume {{ $labels.volume }} is at {{ printf \"%.1f\" $value }}% capacity. Consider expanding or cleaning up."
+          # Volume degraded
+          - alert: LonghornVolumeDegraded
+            expr: longhorn_volume_robustness != 1
+            for: 5m
+            labels:
+              severity: warning
+            annotations:
+              summary: "Longhorn volume {{ $labels.volume }} is degraded"
+              description: "Volume {{ $labels.volume }} robustness is not healthy. Check replica status."
+
+          # Node storage pressure
+          - alert: LonghornNodeStoragePressure
+            expr: |
+              (
+                longhorn_node_storage_usage_bytes 
+                / 
+                longhorn_node_storage_capacity_bytes
+              ) * 100 > 90
+            for: 10m
+            labels:
+              severity: warning
+            annotations:
+              summary: "Longhorn node {{ $labels.node }} storage pressure"
+              description: "Node {{ $labels.node }} disk usage is at {{ printf \"%.1f\" $value }}%."