I’m thinking about sharing a single Redis instance for Discourse and other applications. Is there any page that explains how Discourse does caching? Does it for example prefix everything with “DiscourseAppId_”?
And another related question, would it be possible to have two separate Discourse forums running on the same Redis instance?
If you install multisite then you can use Redis for multiple instances of Discourse.
That said I would strongly recommend NOT shared our Redis DB with any other apps, it will make debugging stuff much more complex. We are namespaced but still, not recommended.