function _mirrorExists($channel, $mirror)
    {
        $data = $this->_channelInfo($channel);
        if (!isset($data['servers']['mirror'])) {
            return false;
        }

        foreach ($data['servers']['mirror'] as $m) {
            if ($m['attribs']['host'] == $mirror) {
                return true;
            }
        }

        return false;
    }