Varnish cache serving old versions of pages or files
This article was posted in: Web Hosting
What is Varnish
Everyone wants their website to be as fast as possible. Varnish cache is a reverse proxy cache. That means it sits in between your web browser and our backend web servers. Every time someone requests a resource from your website, be that a page, image, or style sheet, for example, Varnish will try to intelligently cache a local copy of that resource, so that it can serve the same request in future.
Why use Varnish?
Varnish is several times faster than our backend web servers, so Varnish is especially good as a site optimisation tool.
What problems can arise?
However, in a shared environment, it is not possible to meet the needs of every single customer exactly.
In some cases, content that you would want to be cached, isn't - and in others, content that you would rather not be cached, may be. It's always a compromise, but we feel we get things about right for the majority of our customers.
What Symptoms might I experience
The most common symptom by far is after you update images or CSS files, and the public websites doesn't reflect these changes for some time.
Sometimes you may want to turn the cache off permanently, or empty the cache contents, so you can see the most recent changes to your site.
To access the Varnish cache management screen
Log into cPanel, and look for the SOFTWARE section of icons - click on the xVarnish Caching & Security icon.
Purge or Disable Cache completely
For each of your domains you can:
1.) Turn the cache on and off completely
2.) Purge the contents of the cache so that any changes made to your site will be immediately available to visitors
3.) Development Mode simply disables the cache and activates a timer (6Hrs at the time of writing) after which time the cache is re-enabled - xVarnish obviously know how forgetful developers can be!