er one or more of
                the values:
            </p>
          <div class="itemizedlist">
            <ul type="disc">
              <li>
                <p>
                        <code class="literal">DB_BACKUP_CLEAN</code>
                    </p>
                <p>
                        Before performing the backup, first remove all
                        files from the target backup directory tree.
                    </p>
              </li>
              <li>
                <p>
      