Managed Object Reference (MoRef) ID uniqueness and duplicate IDs in multi-vCenter environments

Products

• VMware vCenter Server

Issue/Introduction

1. A Managed Object Reference (MoRef) ID, such as vm-100, is a unique identifier assigned by vCenter Server to inventory objects. Users may observe identical MoRef IDs assigned to different virtual machines when operating in multi-vCenter environments.
2. Multiple virtual machines across different vCenter Server instances share the same MoRef ID (e.g., vm-602276).
3. Third-party tools or scripts report duplicate IDs in consolidated reports.

Environment

• VMware vCenter Server 7.x
• VMware vCenter Server 8.x

Resolution

Identical MoRef IDs existing on different vCenter Servers do not cause production impact or risks to the vCenter Server environment. vCenter Server manages these IDs independently within its own database.

Key Facts regarding MoRef IDs:

• MoRef IDs are unique only within the scope of the specific vCenter instance that generated them.
• For unique identification across multiple vCenter instances, use the instanceUuid or BIOS UUID.
• A MoRef ID is persistent as long as the object remains in the vCenter inventory. If a VM is deleted, its MoRef ID is retired and will not be reused for new VMs.
• Unregistering and re-registering a VM, or migrating a VM between vCenters (without HCX/Advanced Cross vCenter vMotion), results in the assignment of a new MoRef ID.

To identify the MoRef ID (MOID) via PowerCLI, run the following command: (Get-VM -Name <VM_Name>).ExtensionData.MoRef.Value

Additional Information

Can VM-ID be reused if the original VM is deleted?

Unique ID for a Different vCenter

MoRef ID uniqueness across ELM- William Lam