This is a defect in vCenter. The vCenter caches the value. If it is not accessed for long enough then it is dropped from the cache and is not discoverable. This is mentioned in the docs.

Hello Andrew,

I read the documentation and further discussions about this problem. But I am wondering why BMC taking serial number from hardware.systemInfo. Why you do not use esxcli.hardware.platform.get().SerialNumber when you have a problem with service tag attribute in System Info? We tested esxcli.hardware.platform.get().SerialNumber command on machines from which we did not receive the serial numbers and it works well.

Thanks in advance for response,

Ondrej

From what you have written it looks like you are trying to suggest using the vSphere PowerShell plugin. There is no support to do this. The discovery is currently done on Linux and the PowerShell support Microsoft provide is very flaky.

Yes, you are right we used for this Powershell plugin. Then this is little bit problematic situation. Serial numbers are disapearing because of vmware issue and we can not use the Powershell plugin. Is there any other suggestions except reboot of ESX servers?

Thanks