uranus ~ # mdadm -A -Nswap mdadm: invalid option -- 'N' Usage: mdadm --help for help uranus ~ # mdadm -A -N swap mdadm: invalid option -- 'N' Usage: mdadm --help for help uranus ~ # man mdadm uranus ~ # mdadm -A --name swap mdadm: an md device must be given in this mode uranus ~ # mdadm -A /dev/md3 --name swap uranus ~ # mdadm -A /dev/md3 --name swap uranus ~ # mdadm -A /dev/md3 -N swap mdadm: invalid option -- 'N' Usage: mdadm --help for help uranus ~ # Read man mdadm, and you will see that "-N" should be a valid option.
current man page says that -N applies only to "create, build, or grow". assemble is none of those, so rejecting -N is correct behavior.