This is one we don’t talk about that much, maybe because it’s not a typical plugin or a theme, but without it many large blog sites simply wouldn’t be able to exist, and so we just couldn’t leave it out of this ‘best of’ list.

The Multi-DB functionality is essentially what it says it is, as the standard WordPress MU installation requires only one database – which is great for hobbyists or people just looking to host a few dozen or few hundred sites, but if you want to grow over that… or require more redundancy, security and performance… you are going to want more!

You can use Multi-DB on a new site or an existing site – and you don’t need to be a technical genius to work it out (it’s also exceptionally well documented and supported in our forums).

It allows you to split your single database into 16, 256 or 4096 database – and if you are using cPanel, even incorporates a script that will do that for you.

After that it’ll distribute your blogs around the databases evenly – giving you peace of mind, much better performance and the confidence to grow your site as much as you desire!

It’s the same solution we use on Edublogs.org and is very similar to that which was used on WordPress.com – especially in their earlier days.

And it’ll change the way you think about WPMU, and that’s a promise!

You can download Multi DB here.