The disk format of Virtual Machines doesn't change from thick to thin after migration to a vSAN 8.x cluster

Products

• VMware vSAN 8.x

Issue/Introduction

Following migration of Virtual Machine(s) to a vSAN 8.x cluster, the disk format might remain thick even if user selects vSAN Default Storage Policy (or any other Storage Policy that defaults to thin disk format) in the Select storage step of the VM migration workflow.

Environment

vSAN 8.x

Cause

Value of thinProvisioned field in vpxd daemon's RelocateSpec isn't correctly assigned. 

Resolution

This issue is resolved in ESXi 8.0 P05. 

Additional Information

Workaround:

For any Virtual Machines that are already migrated and reporting 'thick' disk format (despite 'thin' Storage Policy applied), a following workaround is suggested:

•  Make a temporary exact clone of Storage Policy Virtual Machine currently uses.
•  Assign newly created Storage Policy to the affected Virtual Machine. 
•  Once completed, assign original Storage Policy to the Virtual Machine. 

REF: https://techdocs.broadcom.com/us/en/vmware-cis/vsan/vsan/8-0/vsan-administration/using-vsan-policies.html