Cannot expand 'Independent - Nonpersistent' disk on virtual machine

Products

• VMware vSphere ESXi 8.0

Issue/Introduction

• Disks in nonpersistent mode behave like read-only disks. Changes made to disks in nonpersistent mode are discarded when the virtual machine is powered off or reset. With nonpersistent mode, the virtual machine can be restarted with the virtual disk in the same state each time. Changes to the disk are written to and read from a redo log file, which is deleted when the virtual machine is powered off or reset, or when a snapshot is deleted. See disk mode introduction
• The virtual machine is a VDI(Virtual Desktop Infrastructure) desktop virtual machine, and no snapshot.
• 'Independent - Nonpersistent' disk expand option is grayed out even though the VDI desktop virtual machine is in power off status.

Environment

VMware vSphere ESXi 7.x
VMware vSphere ESXi 8.x

Cause

• 'Independent - Nonpersistent' disks are designed to be temporary for desktop virtual machines, with all changes discarded upon shutdown or reset. Expanding the disk size would defeat this intended purpose.
• The non-persistent attribute is applied at the VDI master image level, not on the individual disk. Any attempt to expand the disk from vSphere is blocked by VDI management to ensure consistency and policy enforcement.

Resolution

To increase disk capacity while maintaining a non-persistent setup, create a new master image with the required disk size.

Additional Information

Do not change the mode of the virtual disk оn a running virtual machine, see ESXi 8.0 Update 1c release note
Editing the disk mode of a running virtual machine using the VMware Host Client, for example from Independent - Nonpersistent to Dependent or Independent - Persistent, causes the operation to fail and may result in the VM failure. Errors such as the following can be seen in the vmware.log:

msg.disk.notConfigured2] Failed to configure disk 'scsi0:4'. The virtual machine cannot be powered on with an unconfigured disk.
[msg.checkpoint.continuesync.error] An operation required the virtual machine to quiesce and the virtual machine was unable to continue running.

This issue is resolved in ESXi 8.0 Update 1c. The fix blocks changing the mode of an Independent - Nonpersistent disk on a running virtual machine by using the VMware Host Client. The vSphere Client already blocks such operations.