Web Server Accelerator Array -- Setup

Using the Web Server Accelerator Array

To use the JTAN Web Server Accelerator Array, you need to change where web browsers are looking for your page. You need to send them to the web accelerator cache mirrors rather than to your actual web server. Typically this is done by setting DNS records. In summary, your DNS needs to accomplish two things:

The name "www.yoursite.com" must point to the accelerator hostname, which is "mirror.jtan.com". Using a CNAME is best, as the JTAN hostname resolves to more than one IP, and this list can change.
The name "direct.www.yoursite.com" must still point to your actual web server IP. An A record is best here.

The first step is always needed, but sometimes the second step is not. Many JTAN accounts have a DNS setup with a wildcard "*.yoursite.com" that would automatically point "direct.www.yoursite.com" to the actual, "parent" web server IP.

More names than "www.yoursite.com" can be sent to the accelerator using additional CNAMEs. For example, you could send "yoursite.com" to the accelerator. If you do this, be sure that "direct.yoursite.com" resolves to your actual, parent, web server IP.

If the page isn't cached, the accelerator tacks the prefix "direct." in front of the hostname and attempts to get it directly from the parent web server.

If you understand the above principle, you can see how to have a limited part of your site accelerated. For example, suppose you wanted to accelerate "media.yoursite.com", but leave the rest of your site alone. You could do that by making a CNAME to point "media.yoursite.com" at "mirror.jtan.com", along with an A record that points "direct.media.yoursite.com" at your webserver IP. Again, a default wildcard A record *.yoursite.com can handle the second part. You just need to add the CNAME.

Example -- Accelerating your Whole Site

This example assumes a default JTAN DNS configuration. The domain is "yoursite.org" and the parent webserver IP is "192.168.1.1". Please replace these with your own domain and IP. Here's what the JTAN members area DNS editor looks like with both "yoursite.org" and "www.yoursite.org" sent to the mirror.

Full Site Accelerator Example

When studying the above example, note how the hostnames "direct.www.yoursite.org" and "direct.yoursite.org" are sent to 192.168.1.1 by means of the single wildcard.

Example -- Accelerating Part of your Site

Now let's see how to accelerate just part of a site. We will indicate what parts of the site are accelerated by referring to them with a different hostname in the URL. Normally we refer to files in the site with URLs like "http://www.yoursite.org". These will be served without acceleration, as usual. But if we refer to a file with a link using a URL like "http://media.yoursite.org" it will be accelerated.

Again, this example assumes a default JTAN DNS configuration for domain "yoursite.org" with a parent webserver IP at "192.168.1.1". Here's the DNS setup:

Partial Site Accelerator Example

Again, we rely on the "*.yoursite.org" wildcard to send "direct.media.yoursite.org" to the parent webserver at 192.168.1.1, with "media.yoursite.org" going to the mirror.

Hints and Tips

We realize that accelerator setup can be a little confusing, especially if your are planning to accelerate only part of your site. Please contact us if you have any questions or need assistance.

The following list includes some tips that you may find useful:

Before sending www.yoursite.com to the accelerator, be sure that direct.www.yoursite.com goes to the actual site.
If you expect to change the DNS configuration, lower the TTL value for the DNS records you plan on changing. Do this a day or two before you start playing. This allows you to more quickly see the results of your changes. Then, when things are settled, put them back to their default values.
Get your site alias or subdomains working first, before you make DNS changes.
It's possible to use subdomain rewriting to serve part of your site. JTAN ProWeb premium sites have an option for automatic subdomains. Be sure to use the "Rewrite" option. The magic prefix "direct." is automatically stripped out by the rewriting just like "www." is. Thus, if Rewrite is enabled, the webserver will look for both "direct.media.yoursite.com" and "media.yoursite.com" files in a subdirectory named "/media", not the domain's base document root directory.
Some PC operating systems can be stubborn about changing DNS; some browsers stubbornly cache stale pages. Reboot and flush your browser cache before reporting strange DNS problems or stale pages.