You can specify the number of days an event is retained in the Unified Manager server before it is automatically deleted. Only events that are resolved, obsolete, or of type Information are deleted. You can also specify the frequency with which these events are deleted or you can also manually delete the events.
Retaining events for more than 180 days affects the server performance and is not recommended. The lower limit for the event retention period is 7 days; there is no upper limit.