The guide on setting up multisite says that plugins and components might not work with it. I’d imagine things like Data Explorer would be likely to break as there are multiple databases now, i can’t really get a grip on what else would be likely to break.
I’d really appreciate if anyone who is running a multisite could give me an idea of whether that means that a lot of them don’t work, or that there are one or two out there you’ve encountered which don’t.
I’m running a multisite server since about two years and I never had a plugin breaking just because of multisite.
Some caveats: I run it for staging themes, not for production. So I probably don’t get into the ins and outs of each plugin. Also never used the Data Explorer on additional instances. However, I frequenly rebuild and have quite a list of changing plugins.
At Communiteq we’ve been running a gazillion multisites for over 10 years and I can only name a handful of plugins that had issues.
Most of those use GlobalSettings or ENV variables so there can be no distinction between the different forums. I know the OneSignal plugin used to (?) have issues with that. You have to configure the API key at the multisite master or it wouldn’t work.
Another one was the Discord bot plugin (because it uses a gem that spawns threads) but that has been fixed for sure.
Generally, you should be ok and it’s not something to worry about. The plugin API does a very good job at abstracting away the gory details of multisite.