not found something about thick or this in this doc :
svmotion --url= https://myvc.mycorp.com/sdk
--vm='[old_datastore] myvm/myvm.vmx: new_datastore'
How to tell I need 'eager zeroed thick' ? I have 'lazy thick'
I prefer to not use 'vmkfstools' if possible, it's very long to extend a disk with this.
You can use PowerCLI to achieve such a conversion. Like you said, you can perform an sVMotion of a disk and specify a new storage format. PowerCLI's Move-VM and Move-HardDisk cmdlets each have a parameter that allow for specifying the storage format of the hard disk(s) after the move. An example of moving a VM and setting its storage format to eager zeroed thick:
Move-VM myVM0 -Datastore myDstore0 -DiskStorageFormat EagerZeroedThick -RunAsync
You can use these commands with powercli, not sure if commands are same on vCLI as I dont use it.