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http://timoqi.blogbus.com/logs/21046506.html

翻译自：http://developer.yahoo.com/performance/rules.html

译者:Timo

发布格式：黑色为英文原文，红色为中文翻译

发布时间：从2008年5月16日每天1个章节，共10天

发布协议：new bsd

Exceptional Performance : Best Practices for Speeding Up Your Web Site

特别性能：加速你的WEB网站最佳实践

Use a Content Delivery Network

使用内容分发网络（CDN）

tag: server

tag: server

The user's proximity to your web server has an impact on response times. Deploying your content across multiple, geographically dispersed servers will make your pages load faster from the user's perspective. But where should you start?

服务器的远近对于用户访问的响应时间是有影响的。分发你的内容到多个平台多个地区的服务器上将让用户更快加载的页面。但是你从哪里开始呢？

As a first step to implementing geographically dispersed content, don't attempt to redesign your web application to work in a distributed architecture. Depending on the application, changing the architecture could include daunting tasks such as synchronizing session state and replicating database transactions across server locations. Attempts to reduce the distance between users and your content could be delayed by, or never pass, this application architecture step.

首先第一步要实现地理位置上的分发内容，不要尝试去重新设计你的web应用来应对分布式架构。根据应用，改变架构包含了很多艰巨的任务如同步session状态和复制不同地区服务器上数据库事务。试图减少用户和你的内容的距离将被延迟或者从不通过这不应用程序架构。

Remember that 80-90% of the end-user response time is spent downloading all the components in the page: images, stylesheets, scripts, Flash, etc. This is the Performance Golden Rule. Rather than starting with the difficult task of redesigning your application architecture, it's better to first disperse your static content. This not only achieves a bigger reduction in response times, but it's easier thanks to content delivery networks.

记住80%-90%的终端用户响应时间花在了下载页面中的所有组件:图像，样式表，脚本，Flash等等。这个是性能的黄金法则。与其开始复杂的重新设计你的应用程序架构，不如先分发你的静态内容。这样不仅能实现更大的减少响应时间，这应该感谢CDN让这些更简单。

A content delivery network (CDN) is a collection of web servers distributed across multiple locations to deliver content more efficiently to users. The server selected for delivering content to a specific user is typically based on a measure of network proximity. For example, the server with the fewest network hops or the server with the quickest response time is chosen.

一个CDN是web服务器的集合来更有效率的跨地域的分发内容给用户。分发内容给用户的服务器的选取是基于网络的远近范围来进行的。例如：选择服务器根据最小的网络跳数或者根据最小的响应时间来进行的。

Some large Internet companies own their own CDN, but it's cost-effective to use a CDN service provider, such as Akamai Technologies, Mirror Image Internet, or . For start-up companies and private web sites, the cost of a CDN service can be prohibitive, but as your target audience grows larger and becomes more global, a CDN is necessary to achieve fast response times. At Yahoo!, properties that moved static content off their application web servers to a CDN improved end-user response times by 20% or more. Switching to a CDN is a relatively easy code change that will dramatically improve the speed of your web site.

一些大型的网络公司都拥有自己的CDN，但也有一些提供CDN服务的第三方公司如：Akamai Technologies, Mirror Image Internet, or .(国内的有ChinaCache和帝连)。

对于一个刚起步的拥有独立网站的公司，CDN服务的费用是需要被禁止的，但是如果你的目标客户变的十分庞大和全球性的，CDN是非常必要的来实现快速的响应时间。在Yahoo公司，那些静态内容的web服务器已经被移到CDN中，终端用户的响应时间提高了20％或者更高。切换到CDN只需要修改很少的代码就可以迅速的提升你网站的速度。