From the PR:
The ctladm man page incorrectly duplicates content which is confusing. Under the "modify" subcommand it lists the same options as the "remove" subcommand:
modify Modify a LUN size. The backend, the LUN number, and the
size must be specified.
-l lun_id Specify the LUN number to remove.
remove Remove a LUN. The backend must be specified, and the LUN
number must also be specified. Backend-specific options may
also be specified with the -o flag.
-l lun_id Specify the LUN number to remove.I also found another instance of remove instead of modify, but wasn't sure whether this applies.