Do you use Varnish on your servers?
We are using Nginx as a reverse proxy for the Apache service instead of Varnish. Nginx provides better stability, customization options and performance and this is why this is the preferred choice.
The Nginx service is integrated in the SuperCacher tool, for which you can read more in our tutorial.
Varnish can be configured instead of Nginx only on our Dedicated severs with Geeky features.