func (s *xlStorage) GetDiskID() (string, error) {
	s.RLock()
	diskID := s.diskID
	fileInfo := s.formatFileInfo
	lastCheck := s.formatLastCheck

	// check if we have a valid disk ID that is less than 1 seconds old.
	if fileInfo != nil && diskID != "" && time.Since(lastCheck) <= 1*time.Second {
		s.RUnlock()
		return diskID, nil
	}
	s.RUnlock()

	fi, err := s.checkFormatJSON()
	if err != nil {