说明：  随着应用的越来越复杂，对数据同步和存储的要求越来越多，有时候我们面对大量复杂的数据加载和数据同步代价，尤其是如果单服务器无法承载大量应用数据的时候，我们如何可以实现动态扩展服务器已达到负载均衡的目标
(As applications are becoming more complex, the data synchronization and storage requirements are more and more, sometimes we are facing a large amount of data loading and data synchronization costs, especially if a single server cannot load a lot of the time of application data, how can we realize the dynamic extension of the server has reached the aim of load balancing)