When the volume of fired alerts is high, prioritizing and resolving problems is harder.

You can reduce the overall volume of fired alerts without sacrificing visibility if you limit the number of times a given alert definition fires an alert for the same incident.

Use repeating escalations - Assign an escalation that repeats until the alert is fixed. An alert is in escalation cannot re-fire. The use of repeating escalations for all alerts is highly recommended and the best way to control alert volume in vCenter Hyperic.

Fire one alert then disable the definition - You can configure a alert definition to fire once and disable itself until that alert is marked fixed. When the alert is marked "fixed" the alert definition is re-enabled. If you have vCenter Hyperic, you can can define an associated recovery alert to automatically fix the alert when the triggering condition is no longer true.