1.) The answer depends on what you are using for a dB. If you have an Oracle server, no, it will backup on the fly. If you have an access DB on the same server as the QC/TD server, then I believe the service will have to be temporarily stopped, but I'm not positive. Maybe someone else knows for sure.
2.) Again that depends on what DB you are using. We use Oracle so our DBA's do the backup for us.