-h, --help
Display general help message or, after one of the above
options, a mode-specific help message.
--help-options
Display more detailed help about command line parsing and
some commonly used options.
-V, --version
Print version information for mdadm.
-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.
-q, --quiet
Avoid printing purely informative messages. With this,
mdadm will be silent unless there is something really
important to report.
-f, --force
Be more forceful about certain operations. See the
various modes for the exact meaning of this option in
different contexts.
-c, --config=
Specify the config file or directory. Default is to use
/etc/mdadm.conf and /etc/mdadm.conf.d, or if those are
missing then /etc/mdadm/mdadm.conf and
/etc/mdadm/mdadm.conf.d. If the config file given is
partitions then nothing will be read, but mdadm will act
as though the config file contained exactly
DEVICE partitions containers
and will read /proc/partitions to find a list of devices
to scan, and /proc/mdstat to find a list of containers to
examine. If the word none is given for the config file,
then mdadm will act as though the config file were empty.
If the name given is of a directory, then mdadm will
collect all the files contained in the directory with a
name ending in .conf, sort them lexically, and process all
of those files as config files.
-s, --scan
Scan config file or /proc/mdstat for missing information.
In general, this option gives mdadm permission to get any
missing information (like component devices, array
devices, array identities, and alert destination) from the
configuration file (see previous option); one exception is
MISC mode when using --detail or --stop, in which case
--scan says to get a list of array devices from
/proc/mdstat.
-e, --metadata=
Declare the style of RAID metadata (superblock) to be
used. The default is 1.2 for --create, and to guess for
other operations. The default can be overridden by
setting the metadata value for the CREATE keyword in
mdadm.conf.
Options are:
0, 0.90
Use the original 0.90 format superblock. This
format limits arrays to 28 component devices and
limits component devices of levels 1 and greater to
2 terabytes. It is also possible for there to be
confusion about whether the superblock applies to a
whole device or just the last partition, if that
partition starts on a 64K boundary.
1, 1.0, 1.1, 1.2 default
Use the new version-1 format superblock. This has
fewer restrictions. It can easily be moved between
hosts with different endian-ness, and a recovery
operation can be checkpointed and restarted. The
different sub-versions store the superblock at
different locations on the device, either at the
end (for 1.0), at the start (for 1.1) or 4K from
the start (for 1.2). "1" is equivalent to "1.2"
(the commonly preferred 1.x format). "default" is
equivalent to "1.2".
ddf Use the "Industry Standard" DDF (Disk Data Format)
format defined by SNIA. When creating a DDF array
a CONTAINER will be created, and normal arrays can
be created in that container.
imsm Use the Intel(R) Matrix Storage Manager metadata
format. This creates a CONTAINER which is managed
in a similar manner to DDF, and is supported by an
option-rom on some platforms:
https://www.intel.com/content/www/us/en/support/products/122484/memory-and-storage/ssd-software/intel-virtual-raid-on-cpu-intel-vroc.html
--homehost=
This will override any HOMEHOST setting in the config file
and provides the identity of the host which should be
considered the home for any arrays.
When creating an array, the homehost will be recorded in
the metadata. For version-1 superblocks, it will be
prefixed to the array name. For version-0.90 superblocks,
part of the SHA1 hash of the hostname will be stored in
the later half of the UUID.
When reporting information about an array, any array which
is tagged for the given homehost will be reported as such.
When using Auto-Assemble, only arrays tagged for the given
homehost will be allowed to use 'local' names (i.e. not
ending in '_' followed by a digit string). See below
under Auto Assembly.
The special name "any" can be used as a wild card. If an
array is created with --homehost=any then the name "any"
will be stored in the array and it can be assembled in the
same way on any host. If an array is assembled with this
option, then the homehost recorded on the array will be
ignored.
--prefer=
When mdadm needs to print the name for a device it
normally finds the name in /dev which refers to the device
and is shortest. When a path component is given with
--prefer mdadm will prefer a longer name if it contains
that component. For example --prefer=by-uuid will prefer
a name in a subdirectory of /dev called by-uuid.
This functionality is currently only provided by --detail
and --monitor.
--home-cluster=
specifies the cluster name for the md device. The md
device can be assembled only on the cluster which matches
the name specified. If this option is not provided, mdadm
tries to detect the cluster name automatically.
