manage MD devices aka Linux Software RAID

-C, --create
       Create a new array.

-v, --verbose
       Be more verbose about what is happening.  This can be used twice to be extra-verbose.   The  extra
       verbosity currently only affects --detail --scan and --examine --scan.

-l, --level=
       Set RAID level.  When used with --create, options are: linear, raid0, 0, stripe, raid1, 1, mirror,
       raid4, 4, raid5, 5, raid6, 6, raid10, 10, multipath, mp, faulty,  container.   Obviously  some  of
       these are synonymous.

       When  a  CONTAINER  metadata type is requested, only the container level is permitted, and it does
       not need to be explicitly given.

       When used with --build, only linear, stripe, raid0, 0, raid1, multipath, mp, and faulty are valid.

       Can be used with --grow to change the RAID level in some cases.  See LEVEL CHANGES below.

-n, --raid-devices=
       Specify  the  number  of active devices in the array.  This, plus the number of spare devices (see
       below) must equal the number of component-devices (including "missing" devices) that are listed on
       the  command  line  for --create.  Setting a value of 1 is probably a mistake and so requires that
       --force be specified first.  A value of 1 will then be allowed for linear,  multipath,  RAID0  and
       RAID1.  It is never allowed for RAID4, RAID5 or RAID6.
       This number can only be changed using --grow for RAID1, RAID4, RAID5 and RAID6 arrays, and only on
       kernels which provide the necessary support.

-x, --spare-devices=
       Specify the number of spare (eXtra) devices in the initial array.  Spares can also  be  added  and
       removed  later.   The number of component devices listed on the command line must equal the number
       of RAID devices plus the number of spare devices.