This article applies as of PRTG 22
Solving a Dell PowerEdge physical disk validation error
The SNMP Dell PowerEdge Physical Disk sensor monitors disks in PowerEdge servers using Dell OpenManage Server Administrator or iDRAC. This sensor also needs the serial number of a particular disk to recognize it on the system and to be able to monitor it. This is necessary because the order can change in the retrieved list of disks.
If the sensor cannot find a serial number on a disk in the system when you want to add the sensor, you get the error message The validation of at least one of the new objects failed because of the following: Disk: Required field, not defined.
Restart the PowerEdge server
In this case, shut down your PowerEdge server and restart it. The affected disks on the system now provide the serial numbers so that the sensor can work as expected.
You can check if there are missing serial numbers with the free SNMP Tester. Run this tool on the probe system on which the PowerEdge sensor runs and execute an SNMP walk with the following base OID:
If you see empty entries, for example, 188.8.131.52.4.1.674.108184.108.40.206.220.127.116.11.7.1 = "", the serial number is missing for this disk.