Reverse Proxy Caches

  • Patrick Wall's picture
    July 30, 2015

On the internet, a fast website not only is a lot more usable for your visitors, but it increases search rankings and decreases load, as you have less people on your server using up resources all at once.

We recommend our clients have a reverse proxy cache or varnish cache to increase the speed of their websites and handle load a lot cheaper and faster.  What a reverse proxy cache does is make a copy of anything requested of the website and store it for the next time someone asks for it.  It sets a time each of those items expire, and once expired the next time someone requests that item it goes to the web server again and makes a new copy.  Here’s a cool video about that process:

Now this does have some downsides, namely that your content isn’t immediately updated.  How quickly it gets updated can be configured, but the more often it’s updated the more load and slower your website is, and you may even require a lot more servers and cost to handle that load.

In general the time is dynamic as possible, with whole pages in Drupal or similar systems telling varnish to expire themselves each time they’re updated.  But what about images, javascript, and css?  Those are static assets, in that there’s no way they can tell varnish when they’re updated.  We recommend using a different name if possible, or using css aggregation in Drupal or other systems.  If this isn’t possible the standard length of time is 24 hours or more for the update to go through.