In certain situations, you may want to change the format of a virtual machine from ‘Thin Provisioned’ to ‘Thick Provision’. In most cases, thin provisioning is used to optimize the utilization of available storage in a storage pool by over-subscribing capacity with allocation that is needed ‘at the time’.
For example, you have a 100 GB pool but you need to put three 40 GB VM into that pool. You can Thin provision your VMs so that they only take what they need ‘at the moment’ instead of the full 40 GB that would be allocated immediately were you to thick provision your VMs. In other words, the capacity used by a virtual disk with Thin provisioning goes by the size of the files on the disk and not the defined size of the virtual disk. The trade-off is performance. If you have virtual machines that will be running highly transactional applications (SQL for example), you will want them to have their space allocated up-front, so thick provisioning is the way to go.
To change the Provisioning Scheme from Thin to Thick:
- Log into your vCenter 5.5 webclient
- Go to your Storage view from the vCenter home page
- Click on the datastore where the VM you want to change is located. In my case, this is datastore2
- Browse to the folder that contains your VM’s files. This is TL-EDGESIGHT in this example
- Right click the vmdk file, than click ‘Inflate’.
- After the process is completed, your previously ‘Thin Provisioned’ VM will be ‘Thick Provisioned’.