[heydonovan]

Like others have said, I'd ditch Apache/Varnish for Nginx/PHP-FPM with the ngx_cache_purge module. That's what I've done, and it's far easier to maintain. The VCL language has always struck me as overly complicated, but that's just me. Any reason you chose MongoDB over Redis? (I work with MongoDB and Redis on a daily basis, so I was just curious as to why you chose one over the other for session storage).

[smusumeche]

I chose MongoDB because Symfony has a built-in MongoDB session handler that is included with the framework.