vCenter server with thick provisioned disks on vSAN taking up space

Products

• VMware vCenter Server

Issue/Introduction

vCenter server upgraded/deployed using thick provisioned disks, Extra-Large deployment on vSAN, need to convert to thin provisioning per vSAN storage policy to reclaim space. 

Environment

VMware vSAN (all versions)

Cause

Symptoms

- vCenter was deployed to a vSAN Custer using "Thick Provision lazy Zero" disks during configuration. This deployment along with the vSAN default policy in use will allocate 100% of space to disk. 

- vSAN objects OSR attribute is set to thick for affected VM 

# esxcli vsan debug object list --vm-name=vm1 

Policy:
  stripeWidth: 1
      cacheReservation: 0
      proportionalCapacity: 100  <<< Object space reservation attribute is thick 
      hostFailuresToTolerate: 1
      forceProvisioning: 0
      spbmProfileId: aa6d5a82-1c88-45da-85d3-############
      spbmProfileGenerationNumber: 0
      CSN: 1007
      spbmProfileName: vSAN Default Storage Policy

Used:
  63753420800 <<< 63 GB usage
Size:
  1535450808320 <<< 1.5 TB provisioned space 
Type:
  vdisk
Path:
  /vmfs/volumes/vsan:52f4da6bda089860-eaf5############/f3ea5b68-f003-afd9-13ed-############/vm1.vmdk (Exists)

 

Resolution

Convert the vCenter disks to thin provisioning using the below steps. 

1. Clone the current storage policy that is in use naming it <current policy>_clone.  
   Example "vSAN default policy" cloned to "vSAN default policy_clone"
2. Ensure that during cloned policy creation object space reservation attribute  is set to “Thin “
3. Apply the Cloned policy to the VM that has the thick provisioned disks.
   1.  Access the VM's configuration: Right-click on the VM in the vSphere Web Client and select "Edit Settings"
   2.  Navigate to VM Storage Policies: In the Edit Settings dialog, locate and select the "VM Storage Policies" tab 
   3. Edit the storage policy:

To apply the same policy to all disks: Select the desired policy from the dropdown list and click "Apply to All". 
To configure policies for individual disks: Select the "Configure per disk" option and choose a different policy for each virtual disk.

4. Apply the changes:

1. Click "OK" to save the changes and apply the new storage policy to the VM. 
2. Validate that the Disks for the VM are no longer being reported as "Thick Provision lazy Zero" and are being reported as "Thin Provisioned" and that the space usage on the vSAN datastore has decreased. 
3. Reapply the <currnet policy> such as the "vSAN default polity" back to the VM. 

In vCenter web-client  VM should now report as thin provisioned and the correct used space vs provisioned space per the vSAN policy in use.  If the VM is reporting the same used space and provisioned space in vCenter, vMotion the VM to a new host to have it report correctly.