Does this happen with any Local site? Or just a specific site? For example, if you create a new, blank site and try starting/stopping it does it still hang?
Are you running other developer applications simultaneously? That could also cause similar issues. Apps like MAMP, XAMPP, or Docker for example.
Is 2.8 GB the size of your site’s DB? Or where are you getting that data?
Are you working on one particularly large site? Or if you create a new blank site and try to close that does it still take half an hour?
30 minutes is definitely not the norm, and we haven’t been able to recreate this. Unless there is something else unique about the site you are working on your particular machine.
So, again…please: Is there some kind of config file switch I can modify to prevent this database dump on site stop from happening?
To answer your question, no there is not a way to prevent this from happening. If you’d like you could create a Feature Request around this to see if other users would find something like this valuable.