code: public void format() throws IOException {
      this.layoutVersion = FSConstants.LAYOUT_VERSION;
      this.namespaceID = newNamespaceID();
      this.cTime = 0L;
      for (Iterator<StorageDirectory> it =
                             dirIterator(); it.hasNext();) {
        StorageDirectory sd = it.next();
        format(sd);
      }
    }
docs: Format all available storage directories.