I’ve recently set up a WordPress ‘network’ on this server, which allows one WordPress installation to host multiple blogs. Normally WordPress only provides you with one blog, and until version 3.0 a separate product called WordPress Mu added multiple blogs support; however, with the advent of WordPress 3.0 any single blog installation of WordPress can be turned into a network – although it’s best to start afresh. The WordPress Codex has detailed instructions; this post is mostly a reflective one, based on my own experiences.
First of all, setting up a network isn’t really for the faint of heart. You should be reasonably knowledgeable about administering a web server, especially if, like me, you want to set up the network in a non-standard way. You will also discover the limitations of the WordPress Export feature, if you’re migrating an existing blog; whilst it will get your posts, comments and so forth out, you will need to set up the theme and widgets again.
Plugins are a little confusing. They can only be installed by an administrator, but are then available to all blogs. However, an administrator can ‘network activate’ a plugin, which means that it’s active for all blogs and cannot be disabled on individual blogs. Conversely, any plugin that isn’t activated for the whole network can then be activated just on the blogs necessary. And not all plugins will work with multisite installations. Plus there are also ‘network plugins’ that are installed manually to a separate folder, to manage all the blogs at administrator level. It’s not hugely confusing but at first I assumed that all plugins had to be network activated, which they don’t, for example.
Two of the three blogs I’m hosting have separate domain names, although they are all hosted on the same virtual machine. In the end, I used the Domain Mapping plugin, and then symlinked the htdocs folders for each domain to the domain hosting the WordPress installation. This seems to work well, and it’s largely transparent to the user.
The setup is therefore more complicated, but the major advantage of setting up a multisite installation is that you only have one copy of WordPress and the individual plugins to update. I try not to use many plugins, but at least one will have an update each week, and I’d rather not have to update three or four separate installations of WordPress every time a new release is out. It also saves on disk space although that’s not a massive issue for me.
What is worth mentioning is that this blog is still running on its own, plain vanilla single blog WordPress installation. As it’s by far the biggest blog, and the one I’d least like to break, I decided it wasn’t worth merging into a network. Still, that means I only have two copies of WordPress, not 5.
Of course, back when I still ran Movable Type and Melody, setting up an additional blog was much easier. I definitely found that setting up multiple blogs in WordPress is much more difficult than it was in MT, however, on balance, pretty much everything else is easier with WordPress than MT. And, frankly, if you can install MT you should be able to set up a WordPress network.