VMWare: Changing the thick or thin provisioning of a virtual disk

 Purpose

This article provides steps to change the provisioning of a virtual disk from thick to thin, or from thin to thick. The procedure uses the vSphere Client and vCenter Server to perform this task.

Resolution

Caution: Before following these procedures, VMware recommends that you have a valid backup of the virtual machine and enough space to convert the virtual machine's disk(s) from thin to thick.

To change vmdk from Thin to Thick provisioning 

To change the provisioning of a virtual machine base disk from thin to thick from the Datastore Browser:

1. Power off the virtual machine.
2. In vSphere Client, right-click the virtual machine in the inventory.
3. Click Edit Settings to display the Virtual Machine Properties dialog box.
4. Select the appropriate hard disk in the Hardware list.

Note: The Disk Provisioning Type section on the right displays either Thin Provision or Thick Provision.

 

5. Click Cancel to exit from Virtual Machine Properties dialog box.
6. Navigate to the datastore where the VM/ VM disk resides that was identified in Step 4 under Files

7. Select the disk in question, and in the status bar above, you should find the Inflate option. The Inflate option converts the disk to thick provisioned.

 

 

8. Once you've selected the inflate option, you should be seeing a task getting created for the vmdk inflation at the bottom in the Recent Tasks tab. This task usually takes sometime to complete depending on the performance of the array. 
9. After the inflation task is completed, if the VM in question is not reflecting the change, reload the .vmx file. For more information, see Reloading a vmx file without removing the virtual machine from inventory (1026043).

Notes:

• If the Inflate option is grayed out, it indicates that the virtual machine is not powered off or that it is not thin provisioned.
• There should be no snapshots and the conversion is performed on the base disk.

To change vmdk from Thick to Thin provisioning 

To convert a virtual machine base disk from thick to thin provisioning by changing the datastore and performing storage vMotion:
 

Note: This process requires more than one datastore. If only a single datastore exists, you can clone the virtual machine to a destination machine with thin provisioned disks instead of migrating.

1. Right-click the virtual machine and select Migrate.
2. Select Change storage only and click Next.

 

3. In the next window, select the option configure per disk.

3. Select the disk in question which needs to undergo the modification.
4. Under Storage category select the destination datastore and under the Disk Format option select Thin Provision.

5. Validate the required VM Storage Policy and click Next.
6. Review the information on the Review Selections page and click Finish.

Alternatively, virtual machine disks can be cloned to create new Thick or Thin provisioned VMDKs. For more information, see Cloning and converting virtual machine disks with vmkfstools (1028042).