doc: remove or copy volume job

docs/longhorn.md

@@ -61,4 +61,45 @@ longhorn:
     backupTarget: 's3://k3sbackups@us-east-1/longhorn'
     backupTargetCredentialSecret: minio-secret
 ...
-```
+```
+
+## Copy from one Volume to another
+
+```yaml title="copy-job.yaml"
+apiVersion: batch/v1
+kind: Job
+metadata:
+  namespace: default  # namespace where the PVC's exist
+  name: volume-migration
+spec:
+  completions: 1
+  parallelism: 1
+  backoffLimit: 3
+  template:
+    metadata:
+      name: volume-migration
+      labels:
+        name: volume-migration
+    spec:
+      restartPolicy: Never
+      containers:
+        - name: volume-migration
+          image: ubuntu:xenial
+          tty: true
+          command: [ "/bin/sh" ]
+          args: [ "-c", "cp -r -v /mnt/old /mnt/new" ]
+          volumeMounts:
+            - name: old-vol
+              mountPath: /mnt/old
+            - name: new-vol
+              mountPath: /mnt/new
+      volumes:
+        - name: old-vol
+          persistentVolumeClaim:
+            claimName: data-source-pvc # change to data source PVC
+        - name: new-vol
+          persistentVolumeClaim:
+            claimName: data-target-pvc # change to data target PVC
+```
+
+