monitoringUbuntuzabbix
For monitoring some database servers parameters (NOT ZABBIX self), In zabbix I need to create a trigger for checking an item value at every 15 minute and run if the last retrieve value is increase or decrease from now retrieve value.
How to create that trigger?
If the agent is deployed active, and the FW allows each agent to connect back to the server on the correct port, you shouldn't have a problem getting alerts.
But if you have several agents behind a FW you should deploy a Zabbix Proxy, as Jacob mentioned.
If trigger evaluation fails for some reason, you should see an error message in "Configuration" -> "Triggers", on the right hand side:
In this case, if you have just created "mysql.slowqueries" item and it does not yet have data older than half an hour, function "last(0,1800)" (which returns the last value half an hour ago) is going to fail. Once it has data that is older than half an hour, it should work properly.
If this does not help, please post the error message you see and also your Zabbix version.
Best Answer
If you only wish to see whether the last value differs from the previous value, you should use the
diff()function, like so:If you wish to see whether the last value differs from the previous value by a certain amount, you should use the
change()function, like so:If you wish to construct more complicated expressions, you might wish to consider using
prev()andlast()functions to explicitly refer to the last two values. For instance, thediff()example above can be replaced with:You probably also want the trigger to generate multiple successive PROBLEM events by selecting the checkbox on the right of "Multiple PROBLEM events generation". In that case, if an item goes from 0 to 150 to 300, you will be notified on both changes. Otherwise, you will only be notified on the first change.
Also see official documentation for a complete list of available trigger functions.