数据库sharding,横向扩展

学习资料如下：

http://www.cnblogs.com/skyme/p/3459765.html

http://my.oschina.net/anthonyyau/blog/307165

http://www.****.net/article/2014-08-20/2821300

http://www.****.net/article/2014-06-10/2820160

http://www.mysql.com/products/enterprise/fabric.html