How to validate if a VM is using a vmdk file by analysing the vmx file

Products

• VMware vCenter Server

Issue/Introduction

• There are vmdk files in the VM directory which are suspected to be orphans but that needs to be validated.
• This KB provides steps that can be used to validate which vmdk files are being used by the VM.
• The directory path to the VM directory on the ESX host will be the following:
  /vmfs/volumes/DatastoreName/VMFolderName

Environment

VMware vCenter Server

Resolution

• To validate if a virtual machine is utilizing a specific .vmdk file by analyzing the .vmx configuration file, you must search for the fileName parameter associated with the virtual device controllers (SCSI, IDE, or NVMe).
• If the vmdk file is not referenced in the .vmx file, then it is not currently being used by the VM. 
• The directory path to the .vmx file on the ESX host will be the following:
  /vmfs/volumes/DatastoreName/VMFolderName/VMName.vmx
   
• Manual Validation Steps:
  1. Open the .vmx file: Use a text editor (e.g., Notepad++, vi, or Nano).
  2. Locate Disk Controllers: Search for entries starting with scsi, ide, or nvme.
  3. Identify the Filename: Look for the .fileName key associated with a specific vmdk number.

Example Entry:
scsi0:0.present = "TRUE"
scsi0:0.deviceType = "scsi-hardDisk"
scsi0:0.fileName = "VirtualDiskName.vmdk"

• Key Parameters to Inspect:
  • present = "TRUE": Confirms the device slot is active.
  • deviceType = "scsi-hardDisk": Ensures the device is a disk and not a CD-ROM/ISO.
  • fileName: The value here is the relative or absolute path to the .vmdk descriptor file.
    
    
• Advanced Validation via Command Line:
  If you are logged into an ESXi host via SSH, you can quickly grep the file:
  
  grep -i ".vmdk" /vmfs/volumes/DatastoreName/VMFolderName/VMName.vmx

Important Considerations:

• Snapshots: If the VM has active snapshots, the .vmx file will point to a delta disk (e.g., VMName-000001.vmdk) instead of the base disk.
• Absolute vs. Relative Paths: If the .vmdk is in the same folder as the .vmx, only the filename is shown. If it resides on a different datastore, the full path (starting with /vmfs/volumes/...) will be present.
• Multiple Disks: A VM can have multiple disks. Ensure you check all controller increments (e.g., scsi0:0, scsi0:1, scsi1:0).

Additional Information

• The last write\modify time for a vmdk file or its associated data flat.vmdk file can be verified using the following command:
  - stat <filename>.vmdk
- stat <filename>-flat.vmdk