Converting a thick to thin disk in a VMWare ESX / ESXi

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1. Poweroff the virtual machine.

2. Login to the command line (Putty) console of the esxi server.

3. Locate the directory in which the .vmdk (hard disk) file is located.

4. Execute the following command in the command line console.

vmkfstools –i hard-diskfile-thick.vmdk –d thin hard-diskfile-thin.vmdk

where hard-diskfile-thick.vmdk is the thick provisioned hard drive and the hard-diskfile-thin.vmdk is the newly created thin provisioned disk file.

5. Login to the vsphere client.Delete the old hard drive and add new thin provisioned hard drive to the virtual machine.

6. Start the virtual machine with the modified configuration.


Sometimes you may need to use thick provisioned hard drives in order to support clustering feature.In that kind of circumstances you can use the same command with a little modification to convert thin provisioned hard drive to a thick provisioned one.

vmkfstools –i hard-diskfile-thin.vmdk –d thick hard-diskfile-thick.vmdk

You need to follow all the steps mentioned above to execute this command.
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