Hi. I have a ESXI server having multiple VMs. In PRTG I installed several sensores by using the automated search. At first those sensores work fine but after some time (a day or two) all those sensores report

#N SNMP_EXCEPTION_NOSUCHINSTANCE

If I rerun the automated search the sensores are updated and work again. The names or paths however changed. For example the specified path of DISKFREE changed from /vmfs/volumes/768af872-c73f1197-980e-a6f0eb314e47 to /vmfs/volumes/58c932b9-5200f5fa-9ec1-901b0ec3278a.

What do I need to do in order to get those sensores work permanently?

Kind regards
Thomy800

Article Comments

Hi Thomy,

Thanks for your inquiry, we appreciate your contact regarding this matter!

Please provide us with the following information, so we can analyse this further:
- Which vCenter version is installed?
- Which sensor type are you trying to add exactly?
- Are there other SNMP Sensors working correctly on this device?
- Are you trying to add the Sensor on a VM or directly on the ESXi server?

Please also take a look at the SOAP Datastore Sensor and let me know, if it fits your requirements.

Kind regards,
Birk Guttmann, Tech Support Team


May, 2018 - Permalink

Hi,

Thanks for your response.

  • Version: ESXi 6.5.0 (Build 4564106)
  • Sensors: Disk Free and (003) vmk0-vSwitch0 Traffic. Often additionally SNMP CPU Load Sensor and Memory: Real Memory.
  • Some keep working. for example "snmp uptime". I assume only those sensors adressing a specific device are affected.
  • I am trying to add the sensors directly on the ESXi server. The VM sensors work fine.

I have just noticed that sometimes the error messages alter. Additationally to "#N SNMP_EXCEPTION_NOSUCHINSTANCE" I sometimes get "Could not find data for /vmfs/volumes/90215978-69c4d87d-94e6-f2530e01e743".

Kind regards,
Thomy800


May, 2018 - Permalink

Hello there,
thank you for your reply.

What appears to be happening here, is that the name/OID of these volumes is changing. Essentially, when you deploy the sensor, it records the name of the disk/entry that you want to monitor, for example: "/vmfs/volumes/90215978-69c4d87d-94e6-f2530e01e743".

If this changes however (after a reboot, or when changing settings on the ESXi server) PRTG will not able to locate this entry any longer, leading to the described issue/behavior.

Essentially, there's no way for the sensor to keep track if the "identifier" is changing. The SNMP_EXCEPTION_NOSUCHINSTANCE will also come up in similar situations, for example when an OID that was previously available no longer exists.

For ESXi, you might want to have a look at the specific sensors instead:

Best Regards,
Luciano Lingnau [Paessler Support]


Jun, 2018 - Permalink

Hi, thanks for replying.

Is there a way to disable the OID change? How can I replace the SNMP Trafic Sensor by using SOAP?

Cheers, Thomy800


Jun, 2018 - Permalink

Hello thomy800,
thank you for your reply.

You might want to check with the vendor if there's a way to prevent the OID/name change of the volumes you're monitoring with the Disk Free sensor.

As for the SNMP Traffic sensor, is this sensor also affected? Otherwise, you can keep using it.

Best Regards,
Luciano Lingnau [Paessler Support]


Jun, 2018 - Permalink

Yes, SNMP Traffic sensor is also effected. I guess I can live without this sensor... Thanks, though.


Jun, 2018 - Permalink