vCenter object distribution view and VM snapshots
Due to interface layout constraints, only the top layer of a snapshot chain is reflected in the Physical Disk Placement view in the vSphere Web Client. If there is a base disk and the VM is running on a single snapshot, it is the snapshot's physical disk placement that will be reflected, not the base disk's.
Placement information for the entire active snapshot chain is available via the Ruby vSphere Console (RVC). For more information about RVC, please see Chapter 6, Ruby vSphere Console.