Hello Paessler support community.
I have a problem with some of my WMI sensors. We are running PRTG 13.4.7.3674 with a remote probe. I regularly experience that some of my WMI based sensors seems to "freeze" or get "stuck" (but not all of them). An example is a "WMI Vital System Data (V2) sensor" measuring "Memory: Total Physical". When the sensors get "stuck" i experience that they stay in their previous state (most of the time that means "up"), i get no alerts i'm aware of, but data simply stops coming in.
If i look at the device overview i can see that the the sensor is "green"/up, however no data is displayed. Here is a screenshot showing the difference:
A normal working sensor is shown at the top, a frozen one is shown at the bottom with no data (i.e. numbers etc) in it, despite the fact that a primary channel is set.
If i go to the sensor and select "Live Data" i can see that no entries have been added tot he table since the sensor stalled and got "stuck". The one i'm looking at right now has no data for the last one and a half days, yet the sensor is still "green".
If i try to pause the sensor, the system reacts fine and the sensor changes to paused and goes to a blue color. Then i wait a minute and i try to resume it, the system logs acknowledge that i un-pause it, however the sensor is now stuck in pause mode. The right click menus and icons at the top right (check now, etc) all indicate that the sensor is not paused (i.e. i have the option to check now, and the right click menu gives me the option to "pause" but not to resume). However the sensor stays paused and "blue".
If i look at the sensor details i can see that the "Last Scan" is updating as if the sensor is not paused and is scanning every 5 minutes as it should, however the sensor stays "blue" and no new data is added to the data tables.
I have looked in the system logs on the remote probe, and i can find no entries indicating any problems at all, and the rest of the my sensors seem to work fine. I've also tried to go to the settings for the stuck sensor and told it to "write the result of the sensor to a file". However even though the sensor claims that "Last Scan" happens every 5 minutes, i get no files in the "Logs (Sensors)" folder on the remote probe.
This issue has happened multiple times, and the behavior seems consistent from time to time, though i'm unsure what provokes it in the first place. I can usually resolve this issue (until it happens again) by completely restarting the remote probe service, however this is not a workable solution in general since: 1. I do not know of an automated way to detect that this is happening. At the moment i'm relying on manual inspection to "spot" these stuck sensors. 2. Restarting the remote probe frequently is not a stable solution as it causes many sensors to give off odd states and cause noise in the general statistics we can pull from PRTG.
Do you have any ideas as to what could be causing it and how i can resolve this issue? If you need further information, please let me know!
Best Regards Peter
Last change on May 27, 2014 9:10:28 AM by
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