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In practice this means that when there are multiple reports of a "Node down" around the same time, then only the first event will show up on the opEvents dashboard. This type of deduplication is essential for dealing with event storms; it is therefore always active and non-adjustable.
Related to that is the concept of a Flap, which in opEvents is defined as a sequence of state down and back up transitions within a short time frame. opEvents uses the configuration option state_flap_window to define this window, by default 90 seconds. In a flap situation, the up event is marked as flap event, and it's event name is changed to "<state entity> Flap"; it is also marked as associated to the previous down event, and repeat events that don't convey a new state are suppressed.
Programmable Suppression
To provide fine-grained control of how to handle repeated events of any kind, opEvents also supports programmable event suppression. Using this facility the administrator can define flexible rules for when to suppress repeat events, based on the recent event history and some further refinement criteria.
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