private void createSessionFactory() throws Exception {
   locator.setBlockOnNonDurableSend(true);
   locator.setBlockOnDurableSend(true);
   locator.setFailoverOnInitialConnection(true); // unnecessary?
   locator.setReconnectAttempts(-1);
   sf = createSessionFactoryAndWaitForTopology(locator, 2);
 }