I'm trying to use vmkfstools to expand a disk that is shared between two VMs. The VMs each have a SCSI controller set in "Physical" share mode, and then a VMDK file attached to that controller. Both systems see the VMDK just fine. I'd like to be able to expand the VMDK on-the-fly, without shutting down the VMs, but when I try to run vmkfstools -X 100G to bring it from 50G to 100G, I get the following error:
Unable to access file [DATASTORE1] CLUSTEREDVM1/CLUSTEREDVM1_1.vmdk since it is locked.
What do I need to do differently to add space to a clustered VMDK without shutting down the VMs?