@Override
  public void start() {
    // Launch Locators Distributor thread.
    if (notifyLocatorJoinPool == null) {
      notifyLocatorJoinPool = createThreadPool();
    }
  }
The minimum value of max-pool size
geode-wan/src/main/java/org/apache/geode/cache/wan/internal/client/locator/LocatorMembershipListenerImpl.java