manual:config:triggers
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manual:config:triggers [2011/09/28 07:48] martins-v adding 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. |
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| + | 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. | ||
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| + | 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. |
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| + | 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. | ||
| - | The [[2.0:manual:config:triggers:expression|expressions used in triggers]] are very flexible, allowing to create logical tests of various complexity regarding the monitored statistics. | + | You can [[manual:config:triggers:expression|build trigger expressions]] with different degrees of complexity. |