The BES Admin Console allows you to define a retention period for alerts stored in the Business Enterprise Server database and the AlertServer. The retention period is defined in days and is set under Administrative Tools > Server Configuration > Retention Period.
An alert and all its associated events are deleted from the BES database if it’s closed and its last recurrence is over the retention period. For example, if the retention period is set to 31 days, an alert may be 35 days old but still active. As soon as it’s closed it will be removed from the database when the next housekeeping runs as 35 days is > 31 day retention.
For BES we would not recommend anything higher than a 31 day retention period as it is a Real-Time OLTP and having excessive retention may cause performance issues.