VMDKs show a size of 0
VMFS datastores were the VMDKs reside also show 0 in size
var/log/vmkernel.log shows errors "No such partition on target" and/or "No filesystem on the device"
VMware vSphere ESXi (All Versions)
This is due to the VMFS partition and/or LVM is missing from the device. This is typically caused by mounting/mapping a VMFS datastore to non-ESXi OS like Linux or Windows.
Open a case with VMware by Broadcom support for further assistance