private boolean useDefaultDiskStore() {
    assert getDiskStoreName() == null;
    if (!Arrays.equals(getDiskDirs(), DefaultDiskDirs.getDefaultDiskDirs())) {
      return false;
    }
    if (!Arrays.equals(getDiskDirSizes(), DiskStoreFactory.DEFAULT_DISK_DIR_SIZES)) {
      return false;
    }

    DiskWriteAttributesFactory attributesFactory = new DiskWriteAttributesFactory();
    attributesFactory.setSynchronous(false);
    if (attributesFactory.create().equals(getDiskWriteAttributes())) {
      return true;
    }
    attributesFactory.setSynchronous(true);

    return attributesFactory.create().equals(getDiskWriteAttributes());
  }
Return true if all disk attributes are defaults. DWA.isSynchronous can be true or false.
geode-core/src/main/java/org/apache/geode/internal/cache/LocalRegion.java