How to change the thick or thin provisioning of a virtual disk

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Caution: Before following these procedures, it is highly recommended 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 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. Click the Hardware tab and 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. If the disk provision type is Thick, disk provisioning has already taken place. In this case, the disk provisioning is Thin.
  5. Click Cancel to exit out of Virtual Machine Properties dialog box.
  6. Click the Summary tab of the virtual machine.
  7. Under Resources, right-click the datastore where the virtual machine resides and click Browse Datastore.
  8. Double-click the virtual machine folder to display the .vmdk file.
  9. Right-click the .vmdk file, and click Inflate. The Inflate option converts the disk to thick provisioned.
  10. Reload the .vmx file. For more information see Reloading a vmx file without removing the virtual machine from inventory (1026043).


  • If the Inflate option is grayed out, this 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 convert a virtual machine base disk from thick to thin provisioning by changing the datastore and using offline virtual machine migration:

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. Power off the virtual machine.
  2. Right-click the virtual machine, and click Migrate.
  3. Click Change datastore.
  4. Click Next, and select a datastore that is not the same as the current datastore.
  5. From the dropdown, select the Thin Provision virtual disk format.
  6. Click Next, then Finish. You can monitor the progress of the conversion in the Tasks and Events view in vCenter Server.

Follow the below steps to do Storage vMotion from vSphere Webclient for vSphere 5.5:

  1. Right-click the virtual machine and select Migrate.
    1. To locate a virtual machine, select a datacenter, folder, cluster, resource pool, host, or vApp.
    2. Click the Related Objects tab and click Virtual Machines.
  2. Select Change datastore and click Next.
  3. Select “Thin Provision” for the virtual machine’s disks and click Next
  4. Select a virtual machine storage policy from the VM Storage Policy drop-down menu, click Next
  5. Select the datastore location where you want to store the virtual machine files and click Next.
  6. Review the information on the Review Selections page and click Finish.

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