I'm not sure if a normal backup plugin can save the database(s) created in WP 3.03 "upgraded" to MU. I searched online, and I can't find any relevant info yet.
If all sites are virtual, does it mean that MU runs only 1 database or multiple sub-databases?
If so, how can I backup multiple databases from MU?
Which plugin would best fit for MU: WP backup, WP-DB-BACKUP, WP-DB MANAGER, BACKUP WORDPRESS…?