Hi @wayand,

It's probably best to just stick with one, or the other, and you likely won't get much better performance by running both, and likely better performance by just running one (because you'd be able to give more of the systems resources to one of them, instead of splitting the resources over two).

Depending on the type of content you're trying to cache, and your knowledge with each one, would likely suggest the one to run. That said, unless your application is very busy, and you're just looking for a little boost, you're probably going to get that from either one, equally.

The good news is that we have documents describing how to setup both!

Varnish: https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-varnish-with-apache-on-ubuntu-12-04--3
Apache Content Cache: https://www.digitalocean.com/community/tutorials/how-to-configure-apache-content-caching-on-ubuntu-14-04

Let us know if you have any further questions!