12.Memcached 与 Redis 区别

https://www.zhihu.com/question/19645807

http://blog.youkuaiyun.com/u013256816/article/details/51133134

http://blog.jobbole.com/101496/

http://www.infoq.com/cn/articles/tq-why-choose-redis

https://timyang.net/data/Memcached-lru-evictions/