By default, report and Dashboard data is retained for seven days. If Symantec Messaging Gateway already has seven days of data, the oldest hour of data is deleted as each new hour of data is stored. Based on your organization's size and message volume, the disk storage requirements for report data can become quite large. You can modify how long Symantec Messaging Gateway maintains report data.
To specify how long report data is retained
In the Control Center, click Administration > Settings > Reports.
Under Report and Dashboard Expunger Settings, click the Delete data older than drop-down list to select how long Symantec Messaging Gateway keeps your report data.