manual:config:triggers

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manual:config:triggers [2011/09/28 08:38]
martins-v removing duplicate info
manual:config:triggers [2019/02/11 06:57] (current)
martins-v triggers are evaluated based on history only
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 === Overview === === Overview ===
  
-Triggers are logical expressions that are created to represent the current system state. ​+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: A trigger may have the following status:
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 |OK     |This is a normal trigger state. Called FALSE in older Zabbix versions.| |OK     |This is a normal trigger state. Called FALSE in older Zabbix versions.|
 |PROBLEM|Normally means that something happened. For example, the processor load is too high. Called TRUE in older Zabbix versions.| |PROBLEM|Normally means that something happened. For example, the processor load is too high. Called TRUE in older Zabbix versions.|
-|UNKNOWN|In 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. ​ 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.+Triggers are evaluated based on [[:​manual/​config/​items/​history_and_trends|history]] data only; trend data are never considered. 
 + 
 +If time-based functions (**nodata()****date()****dayofmonth()****dayofweek()****time()****now()**) are used in the expression, the trigger is recalculated ​every 30 seconds by a zabbix //timer// process. If both time-based and non-time-based functions are used in an expression, it is recalculated when a new value is received **and** ​every 30 seconds.
  
-You can build [[2.0:manual:​config:​triggers:​expression|trigger expressions]] with different degrees of complexity.+You can [[manual:​config:​triggers:​expression|build trigger expressions]] with different degrees of complexity.