Lets get on the same page with OCI terminology
Mapping is the relationship of a volume, to what storage ports it is presented across.
On some platforms, mapping isn't really a thing - whenever you create a volume, it is implicitly mapped to all FC ports in the array.
On other platforms, you need to decide explicitly across which storage ports you want to present the volume
Masking is granting access to host HBA WWNs for a volume.
OCI can actually help you understand:
Which volumes are neither mapped nor masked
Which volumes are mapped but not masked
Which volumes are masked but not mapped
The above is purely thinking about how the volumes are configured on the array.
Does this make sense?
Does one of those sound like what you are looking for?
Alternatively, simply looking at volumes which exist, but are not part of paths is a different approach that can be taken - is that what you are looking for?
