Invalid Disk Spec for Group when migrating VM with HCX

Products

• VMware HCX

Issue/Introduction

When attempting to migrate a virtual machine using HCX, the migration fails with the error "Invalid Disk Spec for Group."

Environment

VMware HCX

Cause

The VM disk uses the .mvmdk format instead of the standard .vmdk format. HCX migration processes do not support the .mvmdk disk type, which prevents proper processing of the disk specification during migration validation.

Resolution

Convert the .mvmdk disk to standard .vmdk format using the vmkfstools utility:

1. Execute the following command: vmkfstools -i <source.mvmdk> <destination.vmdk> -d thin
2. Update the VM settings to point to the newly created .vmdk file
3. Power on the VM to verify it functions correctly with the new disk
4. Attempt the HCX migration again

The migration should complete successfully after the disk conversion.

If the error persists after following these steps, contact Broadcom Support for further assistance.

Please provide the following information when opening a support request with Broadcom for this issue:

• Migration details (VM Name, Migration ID, Screenshot of error as seen via UI)
• Source and Target HCX log bundles with HCX database dump checked - see Gather Technical Support Logs

Additional Information

• HCX migration validation failure: Disk size exceeds the maximum supported size