Varnish cache is a performance enhancement tool that's used to speed up the load time of pages for viewing by unauthenticated users (e.g. visitors to your site who do not have the ability to log into the site). Varnish cache is different from the regular Drupal site cache you may be familiar with.
The Varnish cache will save output from your website's server and serve it for up to 60 minutes. Practically speaking, this means that a visitor to your site is seeing a snapshot of any given page. If you make a change to a page, the unauthenticated user may not see that change automatically, due to the cache.
You can clear the Varnish cache through your UofMHosting account. This might be useful if, for instance, you have just posted a news item that you want to be viewable to regular site visitors as soon as possible.
Log in to: https://www.uofmhosting.net
- Click on the website name you want to clear Varnish on.
- Click on Tools.
- Choose "Clear Varnish cache."
This will remove all pages in the Varnish cache, not just the page you changed or added.
If you would like the Varnish cache removed from your account, send a request ticket to uofmhosting@umich.edu.