.\" the Free Software Foundation; either version 2 of the License, or
.\" (at your option) any later version.
.\" See file COPYING in distribution for details.
-.TH MDADM 8 "" v3.0-devel2
+.TH MDADM 8 "" v3.0-rc1
.SH NAME
mdadm \- manage MD devices
.I aka
is not a Software RAID mechanism, but does involve
multiple devices:
each device is a path to one common physical storage device.
+New installations should not use md/multipath as it is not well
+supported and has no ongoing development. Use the Device Mapper based
+multipath-tools instead.
.B FAULTY
is also not true RAID, and it only involves one device. It
provides a layer over a true device that can be used to inject faults.
-B CONTAINER
+.B CONTAINER
is different again. A
.B CONTAINER
is a collection of devices that are
managed as a set. This is similar to the set of devices connected to
a hardware RAID controller. The set of devices may contain a number
-of different RAID arrays each utilising some (or all) blocks from a
+of different RAID arrays each utilising some (or all) of the blocks from a
number of the devices in the set. For example, two devices in a 5-device set
-might form a RAID1 used the whole devices. The remaining three might
+might form a RAID1 using the whole devices. The remaining three might
have a RAID5 over the first half of each device, and a RAID0 over the
second half.
.I mdadm
creates a
.B CONTAINER
-device, it just represents the metadata. Other normal arrays (RAID1
-etc) can be created inside that container.
-
-
-.\".I mdadm
-.\"is a program that can be used to create, manage, and monitor
-.\"MD devices. As
-.\"such it provides a similar set of functionality to the
-.\".B raidtools
-.\"packages.
-.\"The key differences between
-.\".I mdadm
-.\"and
-.\".B raidtools
-.\"are:
-.\".IP \(bu 4
-.\".I mdadm
-.\"is a single program and not a collection of programs.
-.\".IP \(bu 4
-.\".I mdadm
-.\"can perform (almost) all of its functions without having a
-.\"configuration file and does not use one by default. Also
-.\".I mdadm
-.\"helps with management of the configuration
-.\"file.
-.\".IP \(bu 4
-.\".I mdadm
-.\"can provide information about your arrays (through Query, Detail, and Examine)
-.\"that
-.\".B raidtools
-.\"cannot.
-.\".P
-.\".I mdadm
-.\"does not use
-.\".IR /etc/raidtab ,
-.\"the
-.\".B raidtools
-.\"configuration file, at all. It has a different configuration file
-.\"with a different format and a different purpose.
+device, the device just represents the metadata. Other normal arrays (RAID1
+etc) can be created inside the container.
.SH MODES
mdadm has several major modes of operation:
system. As each device is detected,
.I mdadm
has a chance to include it in some array as appropriate.
-.P
+
If a
.B CONTAINER
is passed to
.B CONTAINER
will be created, and normal arrays can be created in that container.
.IP imsm
-Use the Intel Matrix Storage Manager metadata format. This creates a
+Use the Intel(R) Matrix Storage Manager metadata format. This creates a
.B CONTAINER
-which is managed in a similar manner to DDF.
+which is managed in a similar manner to DDF, and is supported by an
+option-rom on some platforms:
+.IP
+.B http://www.intel.com/design/chipsets/matrixstorage_sb.htm
+.PP
.RE
.TP
for the given homehost will be reported as such.
When using Auto-Assemble, only arrays tagged for the given homehost
-will be assembled.
+will be allowed to use 'local' names (i.e. not ending in '_' followed
+by a digit string).
.SH For create, build, or grow:
See the section below on RAID_DEVICE CHANGES. The file should be
stored on a separate device, not on the raid array being reshaped.
+.TP
+.BR \-\-array-size= ", " \-Z
+Set the size of the array which is seen by users of the device such as
+filesystems. This can be less that the real size, but never greater.
+The size set this way does not persist across restarts of the array.
+
+This is most useful when reducing the number of devices in a RAID5 or
+RAID6. Such arrays require the array-size to be reduced before a
+reshape can be performed that reduces the real size.
+
+A value of
+.B max
+restores the apparent size of the array to be whatever the real
+amount of available space is.
+
.TP
.BR \-N ", " \-\-name=
Set a
will not try to be so clever.
.TP
-.BR \-a ", " "\-\-auto{=no,yes,md,mdp,part,p}{NN}"
-Instruct mdadm to create the device file if needed, possibly allocating
+.BR \-a ", " "\-\-auto{=yes,md,mdp,part,p}{NN}"
+Instruct mdadm how to create the device file if needed, possibly allocating
an unused minor number. "md" causes a non-partitionable array
-to be used. "mdp", "part" or "p" causes a partitionable array (2.6 and
+to be used (though since Linux 2.6.28, these array devices are in fact
+partitionable). "mdp", "part" or "p" causes a partitionable array (2.6 and
later) to be used. "yes" requires the named md device to have
a 'standard' format, and the type and minor number will be determined
-from this. See DEVICE NAMES below.
+from this. With mdadm 3.0, device creation is normally left up to
+.I udev
+so this option is unlikely to be needed.
+See DEVICE NAMES below.
The argument can also come immediately after
"\-a". e.g. "\-ap".
.BR \-D ", " \-\-detail
Print detail of one or more md devices.
+.TP
+.BR \-\-detail\-platform
+Print detail of the platform's raid capabilities (firmware / hardware
+topology) for a given metadata format.
+
.TP
.BR \-Y ", " \-\-export
When used with
Run any array assembled as soon as a minimal number of devices are
available, rather than waiting until all expected devices are present.
+.TP
+.B \-\-no\-degraded
+This allows the hot-plug system to prevent arrays from running when it knows
+that more disks may arrive later in the discovery process.
+
.TP
.BR \-\-scan ", " \-s
Only meaningful with
There was an error while trying to get information about the device.
.RE
+.TP
+.B \-\-detail\-platform
+Print detail of the platform's raid capabilities (firmware / hardware
+topology). If the metadata is specified with
+.B \-e
+or
+.B \-\-metadata=
+then the return status will be:
+.RS
+.TP
+0
+metadata successfully enumerated its platform components on this system
+.TP
+1
+metadata is platform independent
+.TP
+2
+metadata failed to find its platform components on this system
+.RE
+
.TP
.B \-\-examine
The device should be a component of an md array.
projects / thirdparty / mdadm.git / blobdiff