Let me start off by stating that this is NOT supported…..
I wanted to attach a local drive to a VM, but wanted the ability to move this drive to a physical Windows server at a later time without the time consuming data migration or drive reformatting. Although there is no way to do this through the VIC, there is a way to do this in the console.
First we need to find the disk we want to use as an RDM. This is accomplished by running the following:
ls -al /vmfs/devices/disks/
In this example the disk I needed was vmhba0:1:0:0….. Take note of the string starting with vml.
Now we need to create the placeholder vmdk we will attach to our vm. We do this with the following command:
vmkfstools -r /vmfs/devices/disks/vml.<String we retrieved above> /vmfs/volumes/<Existing DataStore>/<VM Path>/<NAME>.vmdk
Now the only thing we need to do is to add the existing disk to our VM. You will notice the summary shows the new disk as a “Mapped Raw LUN”
Fire up the VM and format the disk for whatever file system you require.
Enjoy