anchor.diff:      case get_storage_node_by_name(Node) of
           {ok, [Cur|_]} ->
               update_storage_node_status(
  -              update, Cur#node_state{error   = Cur#node_state.error + 1,
  -                                     when_is = leo_date:now()});
  +              update, Cur#node_state{error = Cur#node_state.error + 1});
           _ ->
               ok
       end;
  
positive.code:     case get_storage_node_by_name(Node) of
          {ok, [Cur|_]} ->
              update_storage_node_status(
                update, Cur#node_state{error   = 0,
                                       when_is = leo_date:now()});
          _ ->
              ok
      end;
  
negative.code:     #node_state{node = Node, state = State} = NodeState,
      case get_storage_node_by_name(Node) of
          {ok, [Cur|_]} ->
              update_storage_node_status(update, Cur#node_state{state = State});
          _ ->
              ok
      end;
  