What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

PRTG - Combining triggers



(NB: This is a repeat, i can't be sure if my question yesterday occurred, i understand these are moderated but normally this happens during their work day, i am GMT+11)


I need to gate the trigger logic for monitoring backup archives. e.g.

IF file exists if TLM < 1 day Send notification "that we have an old backup" end else Send notification "backup file does not exist" this is unusual end

When i look at the triggers if seems to be an 'or' "file exists" or "TLM"

>> How is this done ?

Also the help for "file exists" says "Set to "File exists" if you want an alert when the file does not exist. Set to "File does not exist" if you want to get an alert when the file exists."

>> What is this alert, can it be tailored ? or is it referring to your own notification ? i.e. what it is saying is unclear to me


multiple prtg triggers

Created on Jan 17, 2014 12:09:41 AM

9 Replies



Which sensor are you using for this, have you looked into the channel limits to define for a folder sensor for example, when something isn't there to alert and when a file is over 1 day also to alert? You might also be able to program a custom sensor to give out different error statuses if you want those to show in the Last Message field.

Created on Jan 17, 2014 1:24:35 PM by  Greg Campion [Paessler Support]



Thanks but i need more input or an url of an example. Surely what i am doing can't be that unusual that some known steps don't exist ? If i use the "monitor time" and the file does not exist, i get a PE031 error message in the console but no notification.

1. Basic File sensor (has "check if", "monitor file content", Monitor File Time" (== TLM in windows speak) 2. have not looked at channels, will have to read what they are.

I'll post back if i can work it out myseldf and hope for more input.


Created on Jan 17, 2014 10:03:30 PM



See http://sdrv.ms/1eY8CgD for some screenshots

Is two triggers allow ?

What does notification est do ?

Is there a way to debug logic and force a scheduled check "now" ?


Created on Jan 18, 2014 2:11:57 AM



The logic behind the options under "Check If" is this:

If you want an alert when the file in the sensor is not there, then check the File Exists. The sensor will be green when the file exists and the sensor will go into error mode if it does not. You can then set up a State Trigger for when the sensor goes down to notify you when the file is not there.

If you check the option File does not exist then the sensor will be green when the file is not there and will alert when the file named in the sensor is there. Again, you can set up a notification for when the sensor is down.

Two notifications are allowed on sensors, you can technically put as many as you want on them.

There is a button in the upper right hand corner call "check now" that will scan the sensor immediately.

The only way that I can think of to set up this sensor would be to set it up to check if the file exists and then put a limit on the channel "Last Modified". If you set up the sensor like this, you would be able to set up a down notification that would notify you when the file is not there, and you can set up the channel limit to change the last message field to show when the file is old. You can set up the messages associated with the Error and Warning limits in the channel settings under Error / Warning Limit messaage. You can also set up the limits on the channel to put the sensor in warning for when the backup is old and notify you based on that.

Created on Jan 20, 2014 1:35:02 PM by  Greg Campion [Paessler Support]

Last change on Jan 20, 2014 1:36:26 PM by  Greg Campion [Paessler Support]



On the debug front, i saw that for normal use (no schedule) you get a "check now" and "simulate error status", HOWEVER for a scheduled sensor you get these greyed out.

I don't understand you logic as both should be valid for a scheduled task..

I suspect if you want to test these type (with schedule) you have to temporarily remove the schedule ?


Created on Jan 20, 2014 11:14:53 PM



Thanks for your feedback but i am still struggling to get on top of this. I have looked at your videos and read most of the manual. Is my settings (see http://sdrv.ms/1eY8CgD ) close to your "If you set up the sensor like this, you would be able to set up a down notification that would notify you when the file is not there, and you can set up the channel limit to change the last message field to show when the file is old." advice ? I am not sure if we are talking about the same things.

If you look at the skydrive picture above i have updated it. You can see a trial set of settings that don't work.

Observations : - It seems channels are added based on sensors added, these have some options but no options to trigger other things - If the file does not exist then there is an internal warning - I have a schedule that does run at 5 am(to avoid issues with files in change during the copy over between 12 and 2pm) , however having a schedule does seem to affect the logic, I have asked in another forum question on aspects of this https://kb.paessler.com/knowledgebase/en/topic/59765-prtg-specific-time-of-day-handling as it is not clear what the various time references mean when you check at a specific time.


Created on Jan 21, 2014 3:16:00 AM



If a sensor is paused by a schedule, you cannot click on the scan now button. While the sensor is running during your schedule, those options are available. The paused status tells PRTG that this sensor is not in use and it will not display any data during this time and in turn doesn't allow for a scan. If you take the sensor out of the schedule so that it's not paused, then you should be able to do on-demand scans.

For the settings that I mentioned, you have the notifications set up incorrectly and do not have channel settings set up. If you want PRTG to send a notification when the sensor is more than 24h old, you have to set up the channel limits for the last modified channel. With the channel limits, if PRTG scans and the file is older than 23h then you can put it into a down status by defining the upper channel limit to be 34h. Then you can define the message that will be associated with that limit. Once you have that limit set up, you can set up a notification to be sent when the sensor is down whcih will include the message that you defined in the limits.

If you also want PRTG to notify you when the file is not there, you have to then select the file exists radio button. If the does not exist, then PRTG will alert you with this option checked. Since you are only doing a check on this sensor once a day, you need to define the notification to notify after a few seconds since the way you have the notification set up now, there would need to be 24h's of continuous down scans for theses notifications to be triggered which isn't possible since you are only scanning once a day and then putting the sensor into a pause mode.


Larger Size

Created on Jan 22, 2014 9:44:57 AM by  Greg Campion [Paessler Support]



Thanks you, i have managed to get a test to trigger using the state trigger approach and setting a limit inside the channel.

For my interest, my can't the threshold trigger we used as i originally had and similar parameters as used in the channel, used in the threshold trigger ?

Thank you

Created on Jan 22, 2014 11:51:11 AM



The threshold trigger functions differently than the channel limits in that the threshold has to be reached for the amount of time in the trigger whereas the channel limit will alert when that channel hits that time limit.

For your old threshold trigger to work, that channel would need to have a value of above 86400 seconds for 2 scanning intervals for that trigger to trip. Since the scanning interval is set to 24 hours, you were only scanning once. Also, the way that the notification and summarization is set in the notification will affect when that notification will be sent. Also, when only using a threshold notification, the sensor will not go into an alert status and will not show a red status.

With the channel limit, as soon as one scan shows that the value is above what you want, it will put the sensor into the error status and will then trigger the state trigger sending out the alert.

Created on Jan 22, 2014 1:13:22 PM by  Greg Campion [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.