Don’t mix: Varnish and Vary: User-Agent
W3 Total Cache sends “Vary: User-Agent” when using Browser Cache. This effectively renders Varnish useless, i.e. brings cache hit rate extremly down because a copy is saved for every User-Agent out there (Ex.: Mozilla, Webkit, etc.). You can come by that issue by either removing the according lines in your .htaccess file, tuning Apache to not send the User-Agent, or, by ignoring the User-Agent in your varnish configuration. We went with the method of adding configuration to our Varnish.
WordPress Setup Using W3 Total Cache With Varnish & Cloudflare
wordpressのW3 Total Cache pluginを使ってvarnishのキャッシュをpurgeする
http://code.tutsplus.com/tutorials/optimizing-wordpress-with-varnish-and-w3-total-cache--cms-21136
General Settings -> Reverse Proxy Enable varnish cache purging Varnish servers: 127.0.0.1
vcl
w3-total-cacheの ini/varnish-sample-config.vcl は vcl 4系ではない
vcl 4の例
vcl 4.0;
https://wordpress.org/support/topic/good-varnish-4-defaultvcl
https://gist.github.com/nadirlc/46987b42447cf8e3be79
http://www.mql.ovh/varnish-4-0-et-w3-total-cache-pour-booster-les-performances-de-wordpress/
https://github.com/mattiasgeniar/varnish-4.0-configuration-templates/blob/master/default.vcl
参考になる。
