When using the Symantec Messaging Gateway (SMG) db-backup command from the Control Center command line interface (CLI), no record of the command's operation or success is logged to the SMG system logs.
This issue has been addressed with the SMG v10.0.2 release. Operation of the db-backup command will be logged to the /data/logs/messages file similar to how the db-restore command is logged:
2013 Apr 30 09:12:02 (info) db-backup: db-backup finished
2013 Apr 30 09:13:34 (info) db-backup: backup file deleted
2013 Apr 30 09:14:02 (err) db-backup: db-backup failed invalid options