1. What will happen if the administrator missed out running "/opt/zimbra/libexec/scripts/migrate20100913-Mysql51.pl" after the upgrade?

2. What will happen if the database is upgraded without executing "zmmailboxdctl stop"?

3. What does zmmailboxdctl service do? Can Zimbra still function with this stopped?

Can I upgrade the database without stopping zmmailboxdctl or do I need to schedule a downtime for doing this?