Creating a Quiesced Snapshot of a Windows Virtual Machine Fails: "Snapshot 0 failed: Failed to quiesce the virtual machine

Products

• VMware vSphere ESXi
• VMware vSphere ESX 8.x
• VMware vSphere ESX 7.x
• VMware vSphere ESX 6.x

Issue/Introduction

• Creating a quiesced snapshot of a windows virtual machine fails.
• In the vmware.log file of the affected virtual machine, there are similar entries like this:
  
  YYYY-MM-DDTHH:MM:SS| vmx| SnapshotVMXTakeSnapshotComplete done with snapshot 'test4': 0
YYYY-MM-DDTHH:MM:SS| vmx| SnapshotVMXTakeSnapshotComplete: Snapshot 0 failed: Failed to quiesce the virtual machine. (40).
YYYY-MM-DDTHH:MM:SS| vmx| ToolsBackup: not enough empty nodes (needed 9, found 6)
  
  where the values provided in the errors can vary.
• There may be similar errors when attempting a clone operation, as this process starts with creating a snapshot.
• Writer.xml files might not be available when a quiesced Snapshot is being taken for a VM. These files are visible under the <VM_Name>_manifests.zip folder which is present in the VM files on the datastore. These writer.xml files are required by 3rd party backup solutions for Virtual machine backups.

Environment

• VMware vSphere ESXi 6.x
• VMware vSphere ESXi 7.x
• VMware vSphere ESXi 8.x
  
  

Cause

Each SCSI Controller can control 15 disks but quiesced snapshots for windows virtual machine require one available slot per existing disk. This issue occurs if the virtual machine has more than seven disks attached to a single controller.

Resolution

1. Create a new thin virtual disk. This allows you to add a new SCSI Controller.
2. Ensure the new thin virtual disk is attached to SCSI1:0 node.
3. Retry creating the quiesced snapshot. You are now able to create the snapshot successfully.

Alternatively, for virtual machines with more than 7 disks on a single SCSI controller, instead of creating a new thin disk and adding this to a new SCSI controller (SCSI1:0):

1. Shut down the virtual machine.
2. Spread out the existing disks between multiple SCSI controllers.
   
   To do this:
   
   
   1. Right-click the virtual machine and click Edit Settings.
   2. Change the Virtual Device Node to your new desired SCSI controller.
      
      
3. Power on the virtual machine.
   
   Note: Use this method if there is limited storage space or limited authority to create new disks.

Additional Information

Enabling and disabling Windows 2008 and later application-consistent quiescing on ESXi/ESX