Undefined class constant 'SERIALIZER_IGBINARY'

$this->_redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_IGBINARY);//设置自动序列化 和反序列化

少了序列化反序列化的扩展

wget http://pecl.php.net/get/igbinary-1.2.1.tgz
tar zxvf igbinary-1.2.1.tgz
cd igbinary-1.2.1
/usr/local/php/bin/phpize
./configure --with-php-config=/usr/local/php/bin/php-config
make
make install
vim /usr/local/php/etc/php.ini 
加上：
extensions=igbinary.so (加载redis 扩展之前)