One of our most commonly requested features is for WordPress Multisite (i.e. Network) users to be able to restore only one specific site, and not the entire network. This is handy if a particular site administrator wants to roll back something on their site, without any risk of changing something elsewhere on the network.
We’re planning to include this feature in our next release; it’s currently undergoing pre-release testing.
In the “restore” dialog, when restoring a backup on and of an existing multisite network, a new option will appear, allowing the user to choose which site to restore. The drop-down is also searchable, in case you have very many sites on your network and don’t wish to scroll through them all. Just choose the site you wish to restore – and you’re done.
In terms of internals (don’t worry if this next bit hurts your head – it’s only for those who are interested in what’s under the bonnet!), this affects the choice of which database tables, and which files from the “uploads” backup (i.e. media library) to restore (or, on a legacy Network install that was upgraded from a version of WordPress earlier than 3.5 (December 2012), the media is stored in the ‘others’ backup, due to living in a different part of the WordPress file hierarchy). In a WordPress Network, plugin and theme files are shared across the whole network (even though particular networks may not have particular plugins available or active) – and individual site owners can’t change these files anyway (which makes sense, since they’re a shared resource).
This feature will be in the next release, for all users of UpdraftPlus Premium (or of the stand-alone Multisite add-on). It will require you to be running WordPress 3.5 or later to use (our general requirement for WordPress 3.2 (released July 2011) as our minimum supported version is not changing – we know that sometimes people need to make a one-off backup of some really old client sites).
David Anderson (lead developer, UpdraftPlus)