Multi-volume file system feature provides the capability for file-to-volume mapping and volume-to-file mapping via the fsmap and fsvmap commands. The fsmap command reports the volume name, logical offset, and size of data extents, or the volume name and size of indirect extents associated with a file on a multi-volume file system. The fsvmap command maps volumes to the files that have extents on those volumes.
fsvmap(1M) manual pages.
The fsmap command requires open() permission for each file or directory specified. Root permission is required to report the list of files with extents on a particular volume.