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manual:config:triggers

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3 Triggers

Overview

Triggers are logical expressions that “evaluate” data gathered by items and represent the current system state.

While items are used to gather system data, it is highly impractical to follow these data all the time waiting for a condition that is alarming or deserves attention. The job of “evaluating” data can be left to trigger expressions.

Trigger expressions allow to define a threshold of what state of data is “acceptable”. Therefore, should the incoming data surpass the acceptable state, a trigger is “fired” - or changes status to PROBLEM.

A trigger may have the following status:

VALUE DESCRIPTION
OK This is a normal trigger state. Called FALSE in older Zabbix versions.
PROBLEMNormally means that something happened. For example, the processor load is too high. Called TRUE in older Zabbix versions.
UNKNOWNIn this case, Zabbix cannot evaluate the trigger expression. This may happen because of several reasons:
- server is unreachable
- trigger expression cannot be evaluated
- trigger expression has been recently changed

Trigger status (the expression) is recalculated every time Zabbix server receives a new value that is part of the expression.

If time-based functions (nodata(), date(), dayofmonth(), dayofweek(), time(), now()) are used in the expression, the trigger is recalculated every 30 seconds.

You can build trigger expressions with different degrees of complexity.