code: public static void makeNameSpaceDataDir(Collection<File> dataDirs) throws IOException {
      for (File data : dataDirs) {
        try {
          DiskChecker.checkDir(data);
        } catch ( IOException e ) {
          LOG.warn("Invalid directory in: " + data.getCanonicalPath() + ": "
              + e.getMessage());
        }
      }
    }
docs: Create physical directory for Name Spaces on the data node
  
  @param dataDirs
  List of data directories
  @throws IOException on errors