In older versions of ESX, you used to be able to run this command to get / set the UUID of VMDK files:
vmkfstools -J getuuid /vmfs/volumes/datastore/VM/vm.vmdk
vmkfstools -J setuuid /vmfs/volumes/datastore/VM/vm.vmdk
If I run vmkfstools now, it doesn't have the "-J" option
How do I get/set the UUID of VMDK files in ESXi 5?