.\" 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 "" v3.2.2
+.TH MDADM 8 "" v3.2.5
.SH NAME
mdadm \- manage MD devices
.I aka
.I mdadm
will be silent unless there is something really important to report.
+.TP
+.BR \-\-offroot
+Set first character of argv[0] to @ to indicate mdadm was launched
+from initrd/initramfs and should not be shutdown by systemd as part of
+the regular shutdown process. This option is normally only used by
+the system's initscripts. Please see here for more details on how
+systemd handled argv[0]:
+.IP
+.B http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons
+.PP
+
+
.TP
.BR \-f ", " \-\-force
Be more forceful about certain operations. See the various modes for
by a digit string). See below under
.BR "Auto Assembly" .
+.TP
+.B \-\-prefer=
+When
+.I mdadm
+needs to print the name for a device it normally finds the name in
+.B /dev
+which refers to the device and is shortest. When a path component is
+given with
+.B \-\-prefer
+.I mdadm
+will prefer a longer name if it contains that component. For example
+.B \-\-prefer=by-uuid
+will prefer a name in a subdirectory of
+.B /dev
+called
+.BR by-uuid .
+
+This functionality is currently only provided by
+.B \-\-detail
+and
+.BR \-\-monitor .
+
.SH For create, build, or grow:
.TP
The file must be stored on a separate device, not on the RAID array
being reshaped.
+.TP
+.B \-\-data\-offset=
+Arrays with 1.x metadata can leave a gap between the start of the
+device and the start of array data. This gap can be used for various
+metadata. The start of data is known as the
+.IR data\-offset .
+Normally an appropriate data offset is computed automatically.
+However it can be useful to set it explicitly such as when re-creating
+an array which was originally created using a different version of
+.I mdadm
+which computed a different offset.
+
+Setting the offset explicitly over-rides the default. The value given
+is in Kilobytes unless an 'M' or 'G' suffix is given.
+
+Since Linux 3.4,
+.B \-\-data\-offset
+can also be used with
+.B --grow
+for some RAID levels (initially on RAID10). This allows the
+data-offset to be changed as part of the reshape process. When the
+data offset is changed, no backup file is required as the difference
+in offsets is used to provide the same functionality.
+
+When the new offset is earlier than the old offset, the number of
+devices in the array cannot shrink. When it is after the old offset,
+the number of devices in the array cannot increase.
+
.TP
.BR \-\-continue
This option is complementary to the
.I mdadm
will not try to be so clever.
+.TP
+.BR \-o ", " \-\-readonly
+Start the array
+.B read only
+rather than read-write as normal. No writes will be allowed to the
+array, and no resync, recovery, or reshape will be started.
+
.TP
.BR \-a ", " "\-\-auto{=yes,md,mdp,part,p}{NN}"
Instruct mdadm how to create the device file if needed, possibly allocating
.BR byteorder ,
.BR devicesize ,
.BR no\-bitmap ,
+.BR bbl ,
+.BR no-\bbl ,
or
.BR super\-minor .
corrupt in some way so that assembling the array normally fails. It
will cause any internal bitmap to be ignored.
+The
+.B bbl
+option will reserve space in each device for a bad block list. This
+will be 4K in size and positioned near the end of any free space
+between the superblock and the data.
+
+The
+.B no\-bbl
+option will cause any reservation of space for a bad block list to be
+removed. If the bad block list contains entries, this will fail, as
+removing the list could cause data corruption.
+
.TP
.BR \-\-freeze\-reshape
Option is intended to be used in start-up scripts during initrd boot phase.
before file system pivot operation and avoids loss of file system context.
Losing file system context would cause reshape to be broken.
-Reshape can be continued later using
-.B\-\-continue
-option for grow command.
+Reshape can be continued later using the
+.B \-\-continue
+option for the grow command.
.SH For Manage mode:
.BR \-a ", " \-\-add
hot-add listed devices.
If a device appears to have recently been part of the array
-(possibly it failed or was removed) the device is re\-added as describe
+(possibly it failed or was removed) the device is re\-added as described
in the next point.
If that fails or the device was never part of the array, the device is
added as a hot-spare.
it will be assumed that bitmap-based recovery is enough to make the
device fully consistent with the array.
-When
+When used with v1.x metadata,
.B \-\-re\-add
can be accompanied by
-.BR \-\-update=devicesize .
-See the description of this option when used in Assemble mode for an
-explanation of its use.
+.BR \-\-update=devicesize ,
+.BR \-\-update=bbl ", or"
+.BR \-\-update=no\-bbl .
+See the description of these option when used in Assemble mode for an
+explanation of their use.
If the device name given is
.B missing
.TP
.BR \-\-detail\-platform
Print details of the platform's RAID capabilities (firmware / hardware
-topology) for a given metadata format.
+topology) for a given metadata format. If used without argument, mdadm
+will scan all controllers looking for their capabilities. Otherwise, mdadm
+will only look at the controller specified by the argument in form of an
+absolute filepath or a link, e.g.
+.IR /sys/devices/pci0000:00/0000:00:1f.2 .
.TP
.BR \-Y ", " \-\-export
When used with
-.B \-\-detail
+.B \-\-detail , \-\-detail-platform
or
.BR \-\-examine ,
output will be formatted as
.TP
.BR \-\-rebuild\-map ", " \-r
Rebuild the map file
-.RB ( /var/run/mdadm/map )
+.RB ( {MAP_PATH} )
that
.I mdadm
uses to help track which arrays are currently being assembled.
but leaves that to
.IR udev .
It does record information in
-.B /var/run/mdadm/map
+.B {MAP_PATH}
which will allow
.I udev
to choose the correct name.
.\".B \-\-size
.\"is given, the apparent size of the smallest drive given is used.
+If the metadata type supports it (currently only 1.x metadata), space
+will be allocated to store a bad block list. This allows a modest
+number of bad blocks to be recorded, allowing the drive to remain in
+service while only partially functional.
+
When creating an array within a
.B CONTAINER
.I mdadm
.PP
.I mdadm
keeps a list of arrays that it has partially assembled in
-.B /var/run/mdadm/map
-(or
-.B /var/run/mdadm.map
-if the directory doesn't exist. Or maybe even
-.BR /dev/.mdadm.map ).
+.BR {MAP_PATH} .
If no array exists which matches
the metadata on the new device,
.I mdadm
.B /dev/md0
out of all such devices with a RAID superblock with a minor number of 0.
-.B " mdadm \-\-monitor \-\-scan \-\-daemonise > /var/run/mdadm"
+.B " mdadm \-\-monitor \-\-scan \-\-daemonise > /run/mdadm/mon.pid"
.br
If config file contains a mail address or alert program, run mdadm in
the background in monitor mode monitoring all md devices. Also write
pid of mdadm daemon to
-.BR /var/run/mdadm .
+.BR /run/mdadm/mon.pid .
.B " mdadm \-Iq /dev/somedevice"
.br
.BR mdadm.conf (5)
for more details.
-.SS /var/run/mdadm/map
+.SS {MAP_PATH}
When
.B \-\-incremental
mode is used, this file gets a list of arrays currently being created.
-If
-.B /var/run/mdadm
-does not exist as a directory, then
-.B /var/run/mdadm.map
-is used instead. If
-.B /var/run
-is not available (as may be the case during early boot),
-.B /dev/.mdadm.map
-is used on the basis that
-.B /dev
-is usually available very early in boot.
.SH DEVICE NAMES
projects / thirdparty / mdadm.git / blobdiff