Health alarm is flagged detected thick-provisioned

Products

• VMware vSAN

Issue/Introduction

• If the VMs are in "Thick provisioning", vSAN datastore usage will be higher.
  
  
• vSAN online health check reports a warning for thick disks provisioned on virtual machines.
  
  

• This health alarm is flagged because vSAN has detected thick-provisioned VMs even though the applied vSAN storage policy has object space reservation set to 0 (Thin-provisioned). It is
  Recommended to reclaim the underlying storage from 'Thick' to 'Thin', which will improve storage utilization.
  
  
• This health alarm will not check VMs deployed by ESX Agent Manager (EAM), as most of the VMs deployed are thick-provisioned by default or VMs with disabled tasks (vm.disabledMethod), for example, NSX Controllers
   

Environment

VMware vSAN 7.x
VMware vSAN 8.x

Cause

This may be caused by the VMs being backed up from a SAN and restored to vSAN, regular storage vMotion shall always provision VMs with thin disks.

Resolution

Apply a cloned vSAN policy 

1. Click "Policies and Profiles" and select “VM Storage Policies.”
   Clone VM Storage Policy.
   
   
2. Apply the Cloned policy to the VM with thick-provisioned disks.
   Right-click on the VM in the vSphere Web Client navigator and select "Edit Settings"
   
   
3. Navigate to VM Storage Policies:
   In the Edit Settings dialog, locate and select the "VM Storage Policies" tab
   
   
4. Edit the storage policy:
   Select the cloned policy from the dropdown list and click "Apply to All". 
   
   
5. Reapply the <current policy>, such as the "vSAN default policy", back to the VM. 

Additional Information