I had to move a couple of VM's from one datastore to another because of a disk swap. After copying them back I noticed it took forever. What happened? The VM's had thin provisioned disks, and after being copied to the other datastore they were thick provisioned. So this only cost me must more time to copy, but it also wastes valuable disk space. I would like that thin provisioned disks stay thin provisioned also after copying.
Is this by design or is this a bug?