大型网站的架构演进以及对mysql与nosql的使用

随着数据量和访问量的增长，网站构架大致有这么几个发展阶段(以PHP+MySQL+Memcached为例)：

1: PHP + MySQL

2: PHP + MySQL (Master + Slaves)

3: PHP + MySQL (Master + Slaves) + Memcached (Middleware)

4: PHP + MySQL (Sharding + Master + Slaves) + Memcached (Middleware)

5: PHP + MySQL (Sharding + Master + Slaves) + Memcached (Middleware) + NoSQL