This article applies to PRTG Network Monitor 13 or later

Checklist: “Not Found” Sensor Warnings when Monitoring ESX Host Server Hardware

Occasionally, sensors in PRTG show a warning status with the message “X elements not found” (or with another number) when monitoring ESX host server hardware. Though, the sensor worked correctly previously. This issue might appear when monitoring with the VMware Host Hardware Status sensor via SOAP, as well as it can be the case when monitoring the server via WBEM or SNMP.

The warning message in PRTG indicates a not properly functioning CIM (Common Information Model) server on the ESX host. The monitoring result for the ESX server will be ‘unknown’ for all hardware devices in this case.

Possible Solutions

In order to get the CIM server working properly again and, thus, receive data with the affected sensor, please consider the following steps. They are ordered from ‘simple solution’ to ‘hard solution’, so try them step by step and check after each one if the corresponding sensor recieves the expected values again.

• Try to restart the CIM server over the vSphere client.
• If the ‘soft’ restart via the vSphere client does not work, enforce a stop of CIM and restart the server over an SSH console. Use the following commands for this purpose: /etc/init.d/sfcbd-watchdog stop /etc/init.d/sfcbd-watchdog start If necessary, try these commands more than once. The ‘stop’ command might fail because of a timeout and is still running when you try to start again. Note: sfcbd means small footprint cim broker daemon.
• Sometimes, the ‘hard’ restart does not resolve the problem either. In this case, rebooting in maintenance mode often works. While in maintenance mode, all VMware services will be restarted:
  • Migrate all virtual machines from the affected host to other hosts.
  • Set the affected host into maintenance mode.
  • Reboot the affected host.
  • Revert the affected host from maintenance mode to normal.

Sometimes, the maintenance mode is sufficient to resolve the error without any other steps. In some cases, the host itself sends data again after a these steps, but in order to receive data via vCenter, an additional restart of vCenter is necessary.