Michael Janzen

A couple of weeks ago I began re-testing a popular WordPress plugin called WP Super Cache. I had tried it before but had installed it incorrectly and crashed my biggest blog. This time I installed it right and it works great. It works by making flat HTML files of your blog’s web pages and moves the traffic load to Apache (the web server software) and off MySQL (the database software).

The benefit of this is that Apache can take the load and MySQL burns up the servers processor, relatively speaking. My host, Media Temple, charges more money when you use more than your fair share of your shared server’s processor. This seems fair and I like Media Temple because their system can auto scale-up to take huge traffic days, and I’ve had several on Tiny House Design.

My testing has shown that WP Super Cache does reduce my cost because it lightens the load on MySQL. It also speeds up my page loads because Apache is incredibly efficient at serving up flat HTML pages and images.

So I highly recommend WP Super Cache but will also warn you to be sure to read all the installation documentation and learn how to back it out if you experience a crash.

Here are screenshots from my GPU usage (processor use) at Media Temple and Google Analytics during the same time period. As you can see traffic was flat and GPU usage remained low.

Above: Control panel on Media Temple that shows low GPU usage.
Below: Report on Google Analytics.

Tiny House Design, my busiest blog is getting more and more traffic everyday. This is a good thing for lots of reasons but I have it hosted on a shared platform at Media Temple and the cost is starting to inch upward. So far it’s very little money but I want to nip it in the bud.

I really like Media Temple and their ability to scale-up on the fly on extremely heavy traffic days but they charge more if you use more than your fair share of CPU time. They call these system resource units GPUs. This seems fair and most people won’t ever get an overage charge.

The Problem – The problem is that if you move past about 100,000 impressions a month with a WordPress blog you begin to tread into the territory of overage charges with Media Temple. The reason is that WordPress blogs uses a lot of database resources.

If you run logging and stats plug-ins on top of that you load up your database server even more which not only slows down your website but could easily drive the hosting cost up.

The Solution – To solve this problem I’m going to try using WP Super Cache again. The first time I tried it I didn’t install it correctly and it crashed my site. This time I think I have it installed right and now theoretically when visitors come to Tiny House Design the cached pages will be served up by Apache (the web server software) and not MySQL (the database software).

You see Apache is very efficient at serving up images and flat html files, which is exactly what WP Super Cache provides. The load on MySQL should now be very light and the CPU overage charges should drop.

If you want to try WP Super Cache I suggest that you keep a copy of your original wp-config.php file handy in case you miss an install step and crash your blog like I did the first time. WP Super Cache rewrites part of your config file and when you disable the plug-in you might run into trouble with that modified config file. To fix a crashed blog and remove WP Super Cache just disable the plug-in and upload your original config file.