diff --git a/charts/helm/checkmate/INSTALLATION.md b/charts/helm/checkmate/INSTALLATION.md
index 75420e6f4..4a2a120b5 100644
--- a/charts/helm/checkmate/INSTALLATION.md
+++ b/charts/helm/checkmate/INSTALLATION.md
@@ -21,7 +21,10 @@ cd checkmate/charts/helm/checkmate
 Edit `values.yaml` to update:
 - `client.ingress.host` and `server.ingress.host` with your domain names
 - `server.protocol` (usually http or https)
-- `persistence.mongo.storageClass` and `persistence.redis.storageClass` with your storageclass
+- **If upgrading**: Migrate persistence settings from flat structure to nested:
+  - Old: `persistence.mongodbSize` → New: `persistence.mongo.size`
+  - Old: `persistence.redisSize` → New: `persistence.redis.size`
+  - Add: `persistence.mongo.storageClass` and `persistence.redis.storageClass` (leave empty for default)
 - Secrets under the `secrets` section (`JWT_SECRET`, email credentials, API keys, etc.) — replace all change_me values
 
 ### 3. Deploy the Helm chart
diff --git a/charts/helm/checkmate/templates/mongodb-statefulsets.yaml b/charts/helm/checkmate/templates/mongodb-statefulsets.yaml
index a4469ba31..8149b77e2 100644
--- a/charts/helm/checkmate/templates/mongodb-statefulsets.yaml
+++ b/charts/helm/checkmate/templates/mongodb-statefulsets.yaml
@@ -37,8 +37,8 @@ spec:
     - metadata:
         name: checkmate-mongo-persistent-storage
       spec:
-        storageClassName: {{ .Values.persistence.mongo.storageClass }}
+        storageClassName: {{ .Values.persistence.mongo.storageClass | quote }}
         accessModes: ["ReadWriteOnce"]
         resources:
           requests:
-            storage: {{ .Values.persistence.mongo.size }}
\ No newline at end of file
+            storage: {{ .Values.persistence.mongo.size | default "5Gi" | quote }}
\ No newline at end of file
diff --git a/charts/helm/checkmate/templates/redis-statefulsets.yaml b/charts/helm/checkmate/templates/redis-statefulsets.yaml
index 6029575b7..acf7c85a8 100644
--- a/charts/helm/checkmate/templates/redis-statefulsets.yaml
+++ b/charts/helm/checkmate/templates/redis-statefulsets.yaml
@@ -25,9 +25,9 @@ spec:
     - metadata:
         name: checkmate-redis-persistent-storage
       spec:
-        storageClassName: {{ .Values.persistence.redis.storageClass }}
+        storageClassName: {{ .Values.persistence.redis.storageClass | quote }}
         accessModes: ["ReadWriteOnce"]
         resources:
           requests:
-            storage: {{ .Values.persistence.redis.size }}
+            storage: {{ .Values.persistence.redis.size | default "1Gi" | quote }}
 {{- end }}
\ No newline at end of file
diff --git a/charts/helm/checkmate/values.yaml b/charts/helm/checkmate/values.yaml
index f6d764daa..a1a1527de 100644
--- a/charts/helm/checkmate/values.yaml
+++ b/charts/helm/checkmate/values.yaml
@@ -46,7 +46,7 @@ secrets:
 persistence:
   mongo:
     size: 5Gi
-    storageClass: change_me
+    storageClass: ""
   redis:
     size: 1Gi
-    storageClass: change_me
\ No newline at end of file
+    storageClass: ""
\ No newline at end of file