系统的可扩展性.doc

系统的可扩展性
When asked what they mean by scalability, a lot of people talk about improving performance, about implementing HA, or even talk about a particular technology or protocol. Unfortunately, scalability is none of that. Don’t get me wrong. You still need to know all about speed, performance, HA technology, application platform, network, etc. But that is not the definition of scalability.
每每和别人提及可扩展性的含义时,很多人开始讨论提高性能,实施高可用性,甚至谈论特定的技术或协议。显然这些并不是可扩展性。不要误会,您当然需要了解关于速度,性能,可用性,应用平台,网络等相关的一切,但这并非可扩展性的定义。
Scalability, simply, is about doing what you do in a bigger way. Scaling a web application is all about allowing more people to use your application. If you can’t figure out how to improve performance while scaling out, its okay. And as long as you can scale to handle larger number of users its ok to have multiple single points of failures as well.
简单地说,可扩展性就是关于如何处理更大规模的业务。比如,Web应用程序就是允许更多的人使用你的服务。如果你不能弄清楚如何提高性能的同时
向外扩展,没关系。只要你能处理更大规模的用户,即使是存在多个单点故障也没有问题。
There are two key primary ways of scaling web applications which is in practice today.
在今天实践中有两个关键的缩放Web应用程序的方式:垂直扩展和水平扩展。
“Vertical Scalability”– Adding resource within the same logical unit to increase capacity. An example of this would be to add CPUs to an existing server, or expanding storage by adding hard drive on an existing RAID/SAN storage.
“垂直扩展“-在同一个逻辑单位添加资源以增加容量。这样的例子比比皆是,比如升级服务器的CPU,比如在RAID/ SAN存储设备上增