Experiments with mod_pagespeed

I’ve spent most of the day working on optimizing my work sites with mod_pagespeed, a Google sponsored Apache extension that provides various features to speed up the loading of your website.

Installation was easy, just install the package from the mod_pagespeed website and enable it like any other Apache extension. The catch came in making it work with all the virtual hosts on my server. After installation 2 problems quickly arose. First, assets such as images were disappearing from our WordPress multi-site installation. Second, the CPU load on the server started to spike far above normal usage.

In the end, the best solution I found was to disable mod_pagespeed globally and enable it only on a per-site basis via the virtualhost configuration. Doing so has brought the CPU down to acceptable loads and visibly reduced the load time on our most important sites. Not bad for a free extension.

When I originally started this post I intended to make it a tutorial on enabling it and working with it in a similar situation. For now however I’m going to hold off until I can fine-tune my own installation a bit before I do so. In the meantime however things are looking promising, the question remains however whether it will actually live up to the promise.