diff --git a/manila/share/drivers/netapp/dataontap/client/client_cmode.py b/manila/share/drivers/netapp/dataontap/client/client_cmode.py
index 06bc321769..128ef16984 100644
--- a/manila/share/drivers/netapp/dataontap/client/client_cmode.py
+++ b/manila/share/drivers/netapp/dataontap/client/client_cmode.py
@@ -1627,6 +1627,38 @@ class NetAppCmodeClient(client_base.NetAppBaseClient):
                     errors[0].get_child_content('error-code'),
                     errors[0].get_child_content('error-message'))
 
+    @na_utils.trace
+    def set_volume_filesys_size_fixed(self,
+                                      volume_name, filesys_size_fixed=False):
+        """Set volume file system size fixed to true/false."""
+        api_args = {
+            'query': {
+                'volume-attributes': {
+                    'volume-id-attributes': {
+                        'name': volume_name,
+                    },
+                },
+            },
+            'attributes': {
+                'volume-attributes': {
+                    'volume-space-attributes': {
+                        'is-filesys-size-fixed': six.text_type(
+                            filesys_size_fixed).lower(),
+                    },
+                },
+            },
+        }
+        result = self.send_request('volume-modify-iter', api_args)
+        failures = result.get_child_content('num-failed')
+        if failures and int(failures) > 0:
+            failure_list = result.get_child_by_name(
+                'failure-list') or netapp_api.NaElement('none')
+            errors = failure_list.get_children()
+            if errors:
+                raise netapp_api.NaApiError(
+                    errors[0].get_child_content('error-code'),
+                    errors[0].get_child_content('error-message'))
+
     @na_utils.trace
     def set_volume_security_style(self, volume_name, security_style='unix'):
         """Set volume security style"""
diff --git a/manila/share/drivers/netapp/dataontap/cluster_mode/lib_base.py b/manila/share/drivers/netapp/dataontap/cluster_mode/lib_base.py
index 5a38a123f9..3b4531e917 100644
--- a/manila/share/drivers/netapp/dataontap/cluster_mode/lib_base.py
+++ b/manila/share/drivers/netapp/dataontap/cluster_mode/lib_base.py
@@ -1325,6 +1325,8 @@ class NetAppCmodeFileStorageLibrary(object):
         """Extends size of existing share."""
         vserver, vserver_client = self._get_vserver(share_server=share_server)
         share_name = self._get_backend_share_name(share['id'])
+        vserver_client.set_volume_filesys_size_fixed(share_name,
+                                                     filesys_size_fixed=False)
         LOG.debug('Extending share %(name)s to %(size)s GB.',
                   {'name': share_name, 'size': new_size})
         vserver_client.set_volume_size(share_name, new_size)
@@ -1336,6 +1338,8 @@ class NetAppCmodeFileStorageLibrary(object):
         """Shrinks size of existing share."""
         vserver, vserver_client = self._get_vserver(share_server=share_server)
         share_name = self._get_backend_share_name(share['id'])
+        vserver_client.set_volume_filesys_size_fixed(share_name,
+                                                     filesys_size_fixed=False)
         LOG.debug('Shrinking share %(name)s to %(size)s GB.',
                   {'name': share_name, 'size': new_size})
         vserver_client.set_volume_size(share_name, new_size)
@@ -1744,6 +1748,11 @@ class NetAppCmodeFileStorageLibrary(object):
         new_active_replica['export_locations'] = self._create_export(
             new_active_replica, share_server, vserver, vserver_client)
         new_active_replica['replica_state'] = constants.REPLICA_STATE_ACTIVE
+
+        # 4. Set File system size fixed to false
+        vserver_client.set_volume_filesys_size_fixed(share_name,
+                                                     filesys_size_fixed=False)
+
         return new_active_replica
 
     def _safe_change_replica_source(self, dm_session, replica,
diff --git a/manila/tests/share/drivers/netapp/dataontap/client/test_client_cmode.py b/manila/tests/share/drivers/netapp/dataontap/client/test_client_cmode.py
index 447d2ace4e..1693b263b5 100644
--- a/manila/tests/share/drivers/netapp/dataontap/client/test_client_cmode.py
+++ b/manila/tests/share/drivers/netapp/dataontap/client/test_client_cmode.py
@@ -3135,6 +3135,37 @@ class NetAppClientCmodeTestCase(test.TestCase):
         self.client.send_request.assert_has_calls([
             mock.call('volume-modify-iter', volume_modify_iter_args)])
 
+    @ddt.data(True, False)
+    def test_set_volume_filesys_size_fixed(self, filesys_size_fixed):
+        api_response = netapp_api.NaElement(
+            fake.VOLUME_MODIFY_ITER_RESPONSE)
+        self.mock_object(self.client,
+                         'send_request',
+                         mock.Mock(return_value=api_response))
+
+        self.client.set_volume_filesys_size_fixed(fake.SHARE_NAME,
+                                                  filesys_size_fixed)
+
+        api_args = {
+            'query': {
+                'volume-attributes': {
+                    'volume-id-attributes': {
+                        'name': fake.SHARE_NAME
+                    }
+                }
+            },
+            'attributes': {
+                'volume-attributes': {
+                    'volume-space-attributes': {
+                        'is-filesys-size-fixed': six.text_type(
+                            filesys_size_fixed).lower(),
+                    },
+                },
+            },
+        }
+        self.client.send_request.assert_called_once_with(
+            'volume-modify-iter', api_args)
+
     def test_set_volume_size_api_error(self):
 
         api_response = netapp_api.NaElement(
diff --git a/releasenotes/notes/bug-1700871-ontap-allow-extend-of-replicated-share-2c9709180d954308.yaml b/releasenotes/notes/bug-1700871-ontap-allow-extend-of-replicated-share-2c9709180d954308.yaml
new file mode 100644
index 0000000000..f29fbe380d
--- /dev/null
+++ b/releasenotes/notes/bug-1700871-ontap-allow-extend-of-replicated-share-2c9709180d954308.yaml
@@ -0,0 +1,4 @@
+---
+fixes:
+  - The NetApp ONTAP driver is now fixed to allow extension and shrinking
+    of share replicas after they get promoted.