Verifying the integrity of hosted virtual machine parent disks

Products

• VMware
• VMware Desktop Hypervisor

Issue/Introduction

This article describes how to correct a modified parent disk. If a virtual machine has a snapshot and a parent disk has been modified it fails to power on.

Symptoms:

• You cannot power on a virtual machine.
• You see one of these errors:
  • Cannot open the disk or one of the snapshot disks it depends on.
  • The parent virtual disk has been modified since the child was created.

cannot-open-disk corrupt-virtual-disk corrupt-vm-files file-missing file-not-found parent-disk-modified parent-virtual-disk-modified restore-snapshot snapshot-data vm-configuration-file vm-files virtual-machine-vmx-file

Resolution

When a snapshot is taken of a virtual machine, a new (redo) virtual disk file is created for each of its original (parent) virtual disks and any changes made to its virtual disks are written to the new virtual disk files. VMware determines the current data written to each virtual disk by examining the difference between the parent virtual disks and the redo virtual disks.

Note: Modifying the parent virtual disks causes the virtual machine to stop functioning.

Caution: VMware recommends that you backup up the entire virtual machine before attempting any of the following procedures.

If a parent disk is modified, you are not be able to power on the virtual machine. This situation can only be corrected by:

1. Ensure the virtual machine is powered off.
2. Restore the parent virtual disk files from a backup taken when the virtual machine functioned.
   
   Notes:
   • The parent virtual disks can be identified as all files that end in .vmdk but do not end in -00000x.vmdk , where x is a number.
   • Do not attempt to use this method if you are having a problem with a Workstation virtual machine that has had a snapshot taken of a snapshot.
     
     
3. Restore all of the virtual machine files from a backup taken when the virtual machine functioned.
   
   Note: Restoring the virtual machine files results in the loss of any data that was changed since the backup was taken.
   
   
4. Remove the snapshot:
   
   Note: Removing the snapshot results in the loss of any data that was changed since the snapshot was taken.
   
5. 1. Delete all files that end in .vmsn , .vmsd , .vmss and -00000x.vmdk from the directory of the virtual machine, where x is a number.
   2. Delete all files and folders that end in .lck from the virtual machine's directory.
   3. Edit the virtual machine's configuration (.vmx ) file.
   4. Look for any entries that include -00000x.vmdk, where x is a number, and delete -00000x , leaving the rest of the entry intact.
   5. Save the edited version of the .vmx file.

Note: For information on locating virtual disk files, see Locating a hosted virtual machine's files (1003880).