I'm currently running multi-site/multinetwork setup.
i've installed multi-db and everything was working correctly. this morning the system went down and displays a database connection error.
if i delete the db.php file in wp-content folder the system comes back up, but I'm sure I'll be missing blogs (490+ in the new global db while only 195 in original db that was used).
I have checked the db-config.php file and all data looks correct.