The WhatsUp Gold Alert Center includes a health monitoring function that alerts when any of the specified thresholds reaches or exceeds a set threshold. One important setting is to trigger an alert whenever the database size exceeds 80% of its capacity (the default threshold value is 80%). This gives you a chance to back up and purge the database of older device data so you do not exhaust database capacity and drop new incoming device data.
For more information, see Configuring a WhatsUp Health threshold.