title: Syncing multiple Varnish Cache servers
body: <p>We have two servers, web1 and web2, each running Apache and Varnish. They are load balanced, with a persistence of 30 mins. </p>
  
  <p>In our testing, we've found some cases were pages are cached on one instance of Varnish (say web1), but not on Varnish on web2.</p>
  
  <p>Is there is a way to keep them in sync? So that when a page is cached (or purged) in web1, it also gets loaded into (or purged from) web2, and vice versa? </p>