OMNINOGGIN

This tutorial will augment the technique of automatically enabling WP-Cache during heavy load with the ability to switch to a low-bandwidth WordPress theme at the same time.

Few reasons to do this

1. WP-Cache messes with your site statistics, so you do not want to leave it on when your site is not being hammered.
2. You don’t want to use a bandwidth efficient theme all the time because it’s not pretty-lookin’.
3. During traffic storms (e.g. Digg Effect), every 1/100 second optimization tweak counts.
4. If you host your site on a shared host, you will most likely have a bandwidth quota. Switching to a leaner theme conserves your bandwidth (duh!)
5. If you host your site on a home connection, your upload is not up to par with most hosting services, so you need to use that small pipe efficiently.
6. Each “IMG” tag, even if it’s a 1×1 pixel gif, requires an HTTP request to your web server. If you have 10 images on your page, and 10 users are loading your page, that’s 100 simultaneous calls to your server already. Leaner themes usually means less/no images, giving Apache some break.
7. If you’re server is non-uber, you don’t deserve to administer it.
Read on…

I am a semi-fan of WP-Cache. On the good side, it reduces strain on apache by staticising WordPress pages. On the bad side, it messes with my site statistics and makes development hard (I always forget that the page I’m working on is being cached). I like my statistics, but what if I suddenly get a traffic storm? If my site gets dugg, there is no time to worry about statistics. I would need all the help I can get to serve pages efficiently. This is why WP-Cache should be off by default and automatically turned on during traffic storms. Read on…

WP-Cache is a Wordpress plugin that improves your Wordpress speed by caching a static version of each dynamic page request and deliverying that static version for subsequent requests to that page. This in combination with Wordpress internal cache, Apache cache, eAccelerator op code cache, and Varnish proxy cache provides the ultimate setup to combat traffic storms if your article gets dugg. *Note* that there is also a method that helps you turn on WP-Cache on demand (only during traffic storms), but I will discuss that in a later article.

If you’ve ever tried to install the WP-Cache plugin for Wordpress just by uploading to the wp-content/plugins directory and activating it via Wordpress Plugins administration, then you know that 99% of the time that method will not work because of some file permission problems.

Here is the proper way to do it: Read on…

Okay I lied, eAccelerator gives a pretty darn high ROI, but setting up a proxy cache gives a comparable or higher ROI. I chose to use Varnish as my proxy cache.

Once installed, Varnish will keep a cache of all objects requested by internet users (e.g. post-generated PHP pages, CSS, javascripts, images) with the goal of off-loading some work from your web server (remember: we won’t want big Apache to do the work only if it has to). Also Varnish takes full advantage of the OS’s virtual memory and advanced I/O features on FreeBSD 6.x making it the optimal choice for my setup.

There were many confusing instructions on the web about how to configure Varnish. Here are the steps I took to setting up Varnish for a signal machine running both Varnish and the web server: Read on…