纵向伸缩 meaning in English

longitudinal extension

Once you have bottlenecked the vertical scaled server machine , you can consider to expand your application cluster to other machines , horizontal scale
一旦您纵向伸缩的服务器受阻，可以考虑扩展您的应用程序群到其他机器，即横向的伸缩。
If your server still has a lot of free cpu cycle , the method you want to try first will be vertical scaling , which multiple server cluster members work in parallel to process the incoming messages
如果您的服务器仍然有许多空闲的cpu周期，您首先应该去尝试的方法将是纵向伸缩，这种方法中，多个服务器群成员并行处理接收的消息。