How to retrieve the DiskType of VirtualDisk?

Hi all,

I am looking of a way to find the disktype of a virtual disk through vCO. I want to mass storage vMotion a bunch of VM but before doing the Storage vMotion I want to validate if the VM has RDM attach to it. If yes, I will skip the storage vMotion.

I find that vm.config.hardware.device has VC:VirtualDisk object in it but this object has no disktype.

I find a VC:VirtualDiskType, but how to retrieve this information for an existing disk?

Thanks.