Optimizing website performance can dramatically increase conversions and loyalty, and decrease costs. Although it may be traditionally viewed as a responsibility of developers, the reality is that sysadmins are also often asked to work on website performance optimization.
The following is intended as a busy sysadmin's "crash course" in optimizing website performance.
As with trying to optimize any process, you should establish a baseline to measure any changes against. Install the Firebug Firefox plugin and Yahoo!'s YSlow add-on to measure your initial performance and verify improvements as you make changes. To see performance changes over time from a consistent external source, you can use free tools like Pingdom's Full Page Test or Octagate's SiteTimer. Also, Google's Webmaster Tools shows optimization suggestions based on the Page Speed tool, and crawl stats for the average time spent downloading a page from your site.
Yahoo!'s research shown in the table below shows 62-95% of the time required to load a page is spent making HTTP requests for non-HTML components like images, scripts, and stylesheets. See the following table for the time spent loading HTML vs non-HTML components for popular websites:
|Site||Time Retrieving HTML||Time Elsewhere|
Another important step in website performance optimization is configuring your web or application server to deliver gzip compressed content. On typical sites, gzipping content reduces text size by 75% and total size by 37%.
Although there are many other things you can do to optimize website performance, this "crash course" in optimization should get you started.