Does unused database hurt MySQL server performance in any way?

Question

If there are some unused databases on MySQL server is it better to remove those from server?

Answer 1

If they're unused then by all means remove them.

However, leaving them around shouldn't hurt day-to-day performance as they aren't referenced by any application.

They will have an impact on the server performance in areas such as backups etc. as they are more data that has to be checked and copied etc.