Enabling / disabling application-consistent quiescing on Windows 2008 & above VMs on ESXi.

Products

• VMware
• VMware vSphere ESXi

Issue/Introduction

This article provides steps to enable and disable Windows 2008 and 2012 virtual machine application-consistent quiescing.

Symptoms:

• In the affected VM vmware.log file, there may be errors similar to:
  
  'VssSyncStart' operation failed: Operation aborted (0x80004004) warning"
YYYY-MM-DDTHH:MM:SS [FFA18B90 verbose 'PropertyProvider' opID=CA0E7426-00005219-58] RecordOp ASSIGN: info.error, task-142530
YYYY-MM-DDTHH:MM:SS [FFA18B90 info 'Default' opID=######26-0000####-58] [VpxLRO] -- FINISH task-142530 -- -- vpxapi.VpxaService.createSnapshot -- 5229b79e-ce92-3d72-81e9-c22f5ec4923d
YYYY-MM-DDTHH:MM:SS [FFA18B90 info 'Default' opID=######26-0000####-58] [VpxLRO] -- ERROR task-142530 -- -- vpxapi.VpxaService.createSnapshot: vim.fault.ApplicationQuiesceFault:
   
• In the affected VM vmware.log file, there may be errors similar to:
   Error when notifying the sync provider
  • Quiesce operation aborted
  • [msg.snapshot.quiesce.vmerr] The guest OS has reported an error during quiescing

Environment

VMware ESXi 6.x
VMware ESXi 7.x
VMware ESXi 8.x

Resolution

In Windows 2008 or later versions, application-level quiescing is performed using a hardware snapshot provider.

After quiescing the virtual machine, the hardware snapshot provider creates two .REDO logs per virtual machine disk, one for the live (ongoing or upcoming) virtual machine writes, and another for the VSS and Writers in the guest operating system to modify the disks after the snapshot operation is complete.

The snapshot configuration information of the virtual machine reports this second .REDO log as part of the snapshot. This .REDO log represents the quiesced state of all the applications in the guest.

To enable Windows 2008 and later virtual machine application-consistent quiescing:

1. Open the VMware vSphere Client, log in to vCenter Server
2. Locate the virtual machine in question, and power off the virtual machine
3. Right-click the virtual machine, choose Edit Settings
4. Click VM Options tab, and select Advanced
5. Click Edit Configuration in Configuration Parameters
6. Click Add parameter
7. In the Key column, type disk.EnableUUID
8. In the Value column, type TRUE
9. Click OK and click Save
10. Power on the virtual machine

Note: To disable application-consistent quiescing, use these steps until step 7, and in step 8 enter FALSE instead of TRUE.

Disable application quiescing without virtual machine downtime by making a configuration change within VMware tools:

1. Within the guest OS, open C:\ProgramData\VMware\VMware Tools\Tools.conf file using a text editor. If the file does not exist, create it.
2. Add these lines to the file:
   
   [vmbackup]
   vss.disableAppQuiescing = true
    
3. Save and close the Tools.conf file
4. Restart the VMware Tools Service for the changes to take effect:
   Restarting of the VMware Tools Service does not reliably stop the vmtoolsd.exe process. Therefore, follow these steps to restart:
   1. Click Start > Run, type services.msc, and click OK
   2. Right-click the VMware Tools Service and click Stop
   3. Open Task Manager. In the Processes tab, search for vmtoolsd.exe
   4. Right-click on vmtoolsd.exe and stop the process
   5. In guest guest OS Services window,  right-click the VMware Tools Service and click Start. Ensure that the vmtoolsd.exe service has restarted in the Processes tab.
      
      Note: In some versions of VMware Tools, this service is named as VMware Tools Service(VMTools)