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sources/tech/20151028 10 Tips for 10x Application Performance.md

@@ -73,19 +73,28 @@ NGINX 经常被用来进行负载均衡；要想了解更多的情况可以访
 ### Tip #3: 缓存静态和动态的内容 ###
 
 Caching improves web application performance by delivering content to clients faster. Caching can involve several strategies: preprocessing content for fast delivery when needed, storing content on faster devices, storing content closer to the client, or a combination.
+缓存通过加速内容的传输速度来提高web 应用的性能。它可以采用一下集中策略：当需要的时候预处理要传输的内容，保存数据到速度更快的设备，把数据存储在距离客户端更近的位置，或者结合起来使用。
 
 There are two different types of caching to consider:
+下面要考虑两种不同类型数据的缓冲：
 
 - **Caching of static content**. Infrequently changing files, such as image files (JPEG, PNG) and code files (CSS, JavaScript), can be stored on an edge server for fast retrieval from memory or disk.
+- **静态内容缓存**。不经常变化的文件，比如图像(JPEG,PNG) 和代码(CSS,JavaScript)，可以保存在边缘服务器，这样就可以快速的从内存和磁盘上提取。
 - **Caching of dynamic content**. Many Web applications generate fresh HTML for each page request. By briefly caching one copy of the generated HTML for a brief period of time, you can dramatically reduce the total number of pages that have to be generated while still delivering content that’s fresh enough to meet your requirements.
+- **动态内容缓存**。很多web 应用回针对每个网页请求生成不同的HTML 页面。在短时间内简单的缓存每个生成HTML 内容，就可以很好的减少要生成的内容的数量，这完全可以达到你的要求。
 
 If a page gets ten views per second, for instance, and you cache it for one second, 90% of requests for the page will come from the cache. If you separately cache static content, even the freshly generated versions of the page might be made up largely of cached content.
+举个例子，如果一个页面每秒会被浏览10次，你将它缓存1 秒，99%请求的页面都会直接从缓存提取。如果你将将数据分成静态内容，甚至新生成的页面可能都是由这些缓存构成的。
 
 There are three main techniques for caching content generated by web applications:
+下面由是web 应用发明的三种主要的缓存技术：
 
 - **Moving content closer to users**. Keeping a copy of content closer to the user reduces its transmission time.
+- **缩短数据与用户的距离**。把一份内容的拷贝放的离用户更近点来减少传输时间。
 - **Moving content to faster machines**. Content can be kept on a faster machine for faster retrieval.
+- **提高内容服务器的速度**。内容可以保存在一个更快的服务器上来减少提取文件的时间。
 - **Moving content off of overused machines**. Machines sometimes operate much slower than their benchmark performance on a particular task because they are busy with other tasks. Caching on a different machine improves performance for the cached resources and also for non-cached resources, because the host machine is less overloaded.
+- **从过载服务器拿走数据**。机器经常因为要完成某些其它的任务而造成某个任务的执行速度比测试结果要差。将数据缓存在不同的机器上可以提高缓存资源和非缓存资源的效率，而这知识因为主机没有被过度使用。
 
 Caching for web applications can be implemented from the inside – the web application server – out. First, caching is used for dynamic content, to reduce the load on application servers. Then, caching is used for static content (including temporary copies of what would otherwise be dynamic content), further off-loading application servers. And caching is then moved off of application servers and onto machines that are faster and/or closer to the user, unburdening the application servers, and reducing retrieval and transmission times.