protected function new_redis($server, $prefix = '', $password = '') {
        $redis = new Redis();
        $port = null;
        if (strpos($server, ':')) {
            $serverconf = explode(':', $server);
            $server = $serverconf[0];
            $port = $serverconf[1];
        }
        if ($redis->connect($server, $port)) {
            if (!empty($password)) {
                $redis->auth($password);
            }
            $redis->setOption(Redis::OPT_SERIALIZER, $this->serializer);
            if (!empty($prefix)) {
                $redis->setOption(Redis::OPT_PREFIX, $prefix);
            }
            // Database setting option...
            $this->isready = $this->ping($redis);
        } else {
            $this->isready = false;
        }
        return $redis;
    }