public function addServer($host, $port = 11211, $weight = 0)
    {
        $key = $this->getServerKey($host, $port, $weight);
        if (isset($this->server[$key])) {
            // Dup
            $this->resultCode = Memcached::RES_FAILURE;
            $this->resultMessage = 'Server duplicate.';
            return false;

        } else {
            $this->server[$key] = array(
                'host'  => $host,
                'port'  => $port,
                'weight'    => $weight,
            );

            $this->connect();
            return true;
        }
    }