上QQ阅读APP看书，第一时间看更新
The x-axis
On the x-axis, this strategy targets the horizontal scalability with the same application server replicated n times in full and in a balanced order of 1/n.
The problem with this strategy is that resources such as databases and caches will be required, since the number of applications that accesses these features gradually increases, as necessary, to scale. For this strategy, caches require more memory and databases need a pool of greater connections, something that does not always result in a benefit:
