This identifies who or what owns this VSAN's policy - typically local versus a value pointing at UCS Central or a template as the actual source of the configuration. When a VSAN's ID or zoning setting seems to silently revert after a manual edit, this field explains why - it tells the admin whether this VSAN is really controlled locally or by an external policy source that will overwrite local changes on the next sync. A VSAN whose ID keeps reverting despite local edits would show a policy owner pointing to UCS Central rather than local, telling the admin to make the change centrally instead.