Changing the thick or thin provisioning of a virtual disk (2014832)

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

Note: Before following these procedures, VMware highly 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 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.

Notes:

• If the Inflate option is grayed out, this may indicate 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:

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.

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.

Source:-

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2014832