Lately I’ve been doing a lot of work with Varnish, this includes testing it within a load balanced environment, putting it behind nginx, putting it in front of Solr, the list goes on.

This blog post will hopefully give you an insight in to a simple way of combining nginx, Varnish and Apache to create a powerful Wordpress environment that can really take a hammering.

I’m going to assume you already have Apache and nginx working together, if not I suggest you read my other articles on these subjects to learn how to combine them.

Installing Varnish

sudo apt-get install varnish

Configuring Apache

I suggest binding Apache to port 81, this is easy to change, open the following file in your favourite editor.

/etc/apache2/ports.conf

Change the Listen and NameVirtualHost lines to:

Listen 81
NameVirtualHost *:81

This will mean you need to go and change all …

The problem

So lets get to the problem first. I have several lightly to medium loaded sites running on some virtual servers, they servers themselves are highly configured to run beautifully on our host environments, very, very RAM intensive but low disk I/O and low CPU usage.

As mentioned, the sites are relatively low loaded, they’ll generally hang around at between 3,000-5,000 unique hits a day and are run through Apache using PHP, various PHP modules and MySQL, a simple generic LAMP environment, yet customised to suit it’s surroundings and host.

The sites themselves run fine on that setup, no issues at all on normal days, but on set days of the week these sites can double in unique hits or even more than double, with KeepAlive enabled and a KeepAliveTimeout set low Apache has problems handling this kind of load (I should point out …