Gzip is a free and open compression method, developed by the GNU project (the same project responsible for a good portion of GNU/Linux). Gzip is also an RFC 1952 standard and is the most popular method for web compression. What essentially happens is that the browser (client) contacts the site (host) and receives a header that indicates that the file can be compressed with gzip. If the browser supports gzip, it will respond and retrieve the compressed file, extract the contents, and display. As a result, it takes less time to download content, thus reducing stress on the server.

Gzip can reduce response size by 70%, which means a tremendous amount of savings on bandwidth. Furthermore, nearly 90% of browsers used on the Internet support it, which includes all modern browsers. The older ones that do not support it are fading away quickly. Apache 1.3 uses a module called mod_gzip, while Apache 2 uses one called mod_deflate. Many content management systems have support for gzip compression built into the backend, if the user choose to enable it.

1. Accessibility. A-Checker – An accessibility testing tool. Simply enter the URL or upload the html file of the site page you want to evaluate, and it will test it according to HTML standards and accessibility standards.

2. Speed. Pingdom Full Page Test – This complete tester will load your entire web page, including images, CSS, flash, and anything else you might have stuck in there. It then evaluates the overall speed as well as each item.

3. Security. Zero Day Scan – An online service that tests your website for security vulnerabilities such as Cross-Site Scripting (XSS), SQL injection, and more. It then generates a report of the test results. Domain ownership verification is required.

An easy way to test your website’s speed in the worst conditions, is to load it on the slowest computer you can find, on the slowest possible connection. The more single-page text, styles, images, and animations you have, the longer it will take for a browser to process it and display it.

There are also two website speed tool tests you can try: iWebTool has a speed test that will measure up to 10 domains at once. It will download your website’s actual pages and tell you how long it takes. Pingdom has a test that will examine the entire page, telling you the load times for each content item, including images. Both tools are useful, and after you have your results, compare them with other websites of similar size and content. Finally, make the necessary changes to your site, and reap the benefits.

Answer: Although there many things to consider when trouble-shooting speed issues, one specific YUM concern might be the speed of the mirror sites used for downloading packages. If download time seems to be the main concern (as opposed to actual installation time), installing yum-fastmirror should help.

This simple program will automatically seek out the fastest YUM mirror servers and then store the metadata in /var/cache/yum/timedhosts.txt. The plugin works by timing all the servers that come up in the mirror list and then selecting the one that is fastest for your location. Locations closer to you on less congested servers usually connect and send data faster. With yum-fastmirror, this can all be configured automatically.

To install the plugin, enter as root:

yum install yum-fastmirror

Answer:

1. Your web host – These is the easy one to assume, that your web hosting company is just offering slow service. But it might not be true. Test it. There are websites that will allow you to do independent traceroutes and other tests to evaluate your host’s network speed. You can also check general things like the CPU speed, RAM, and server load.

2. Check your own connection – You also should not assume that the problem lies elsewhere. Unless you have visited your site from another location, you may very well just have a slow connection on your end, even if you can connect to other sites just fine. Do a traceroute and see if there are any trouble spots between your computer and your server.

3. Optimize images – Image files with huge file sizes will take longer to load. Use an image editing program to make sure all of your images are small enough in size while still maintaining quality.

4. Use XHTML, CSS – Standards compliant websites will be faster. Most web browsers are designed to read XHTML and CSS very quickly. Avoid having inline styles and lots of unnecessary code that must be loaded every time someone accesses your site. Most of all, avoid Flash, Java, and other additional objects unless absolutely necessary.

5. Minimize externally linked scripts – Ads are often necessary, but make sure you choose ad servers that do not slow down your website too much. Some statistical services can cause lag when loading your site. Use them sparingly.

Photo: Flickr