Web Cluster Upgrade: Caching FAQ
Effective January 17,2013 the University of Northern Iowa's web cluster system will be upgraded to the latest stable version of operating system and web server software. Part of this upgrade will include adding a new web site caching feature. The purpose of caching UNI's websites is to relieve the the stress of high traffic sites on the cluster by delivering already generated content.
Who will this affect?
Most notably this will affect Drupal 7 sites and any other websites that are sending a max-age cache control header. The caching software will respect the time specified by those headers.
Will I notice any changes?
Hopefully you will notice a performance boost as your websites load faster than they did before. New content that you add to your site may not be viewable immediately. This will rely on the cache expiration that you can set in the Drupal performance settings.
My site is a Drupal 6 site, should I be concerned?
Our testing has shown that Drupal 6 sites will mostly, not be affected. Drupal 6 does not contain the proper code to inform the caching software to cache pages. Drupal 6 administrators should be more concerned with the fact that Drupal 6 will no longer be supported when Drupal 8 is released. This means there will be no more security/software updates. Drupal suggests that Drupal 8 may be released Fall 2013. It is recommended that you upgrade your sites to Drupal 7 as soon as possible.
Are there file types that will always be cached?
Yes, the following static file types are set to always cache.
Are wwwdev and wwwstage also caching sites?
At this time only wwwstage and the production cluster will be running caching software. Caching sites while they are in development is not appropriate.
Can I limit how long my site is cached?
If your site is running Drupal 7, you can go to the Performance settings in the configuration panel and set the "Expiration of cached pages" setting. If you have previosuly set this value to a high value and attempt to lower it, you may have to wait for the higher value time frame before your site is cleared from the cache.