.\" 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 "" v3.3
+.TH MDADM 8 "" v3.3.4
.SH NAME
mdadm \- manage MD devices
.I aka
.P
If a device is given before any options, or if the first option is
+one of
.BR \-\-add ,
+.BR \-\-re\-add ,
+.BR \-\-add\-spare ,
.BR \-\-fail ,
.BR \-\-remove ,
or
by a digit string). See below under
.BR "Auto Assembly" .
+The special name "\fBany\fP" can be used as a wild card. If an array
+is created with
+.B --homehost=any
+then the name "\fBany\fP" 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.
+
.TP
.B \-\-prefer=
When
and
.BR \-\-monitor .
+.TP
+.B \-\-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.
+
.SH For create, build, or grow:
.TP
.BR \-c ", " \-\-chunk=
Specify chunk size of kibibytes. The default when creating an
array is 512KB. To ensure compatibility with earlier versions, the
-default when Building and array with no persistent metadata is 64KB.
+default when building an array with no persistent metadata is 64KB.
This is only meaningful for RAID0, RAID4, RAID5, RAID6, and RAID10.
RAID4, RAID5, RAID6, and RAID10 require the chunk size to be a power
.B "none"
is given with
.B \-\-grow
-mode, then any bitmap that is present is removed.
+mode, then any bitmap that is present is removed. If the word
+.B "clustered"
+is given, the array is created for a clustered environment. One bitmap
+is created for each node as defined by the
+.B \-\-nodes
+parameter and are stored internally.
To help catch typing errors, the filename must contain at least one
slash ('/') if it is a real file (not 'internal' or 'none').
the number of devices in a RAID0, it is necessary to set the new
number of devices, and to add the new devices, in the same command.
+.TP
+.BR \-\-nodes
+Only works when the array is for clustered environment. It specifies
+the maximum number of nodes in the cluster that will use this device
+simultaneously. If not specified, this defaults to 4.
+
+.TP
+.BR \-\-write-journal
+Specify journal device for the RAID-4/5/6 array. The journal device
+should be a SSD with reasonable lifetime.
+
+
.SH For assemble:
.TP
.BR summaries ,
.BR uuid ,
.BR name ,
+.BR nodes ,
.BR homehost ,
+.BR home-cluster ,
.BR resync ,
.BR byteorder ,
.BR devicesize ,
.BR no\-bitmap ,
.BR bbl ,
-.BR no-\bbl ,
+.BR no\-bbl ,
.BR metadata ,
or
.BR super\-minor .
of the array as stored in the superblock. This is only supported for
version-1 superblocks.
+The
+.B nodes
+option will change the
+.I nodes
+of the array as stored in the bitmap superblock. This option only
+works for a clustered environment.
+
The
.B homehost
option will change the
same as updating the UUID.
For version-1 superblocks, this involves updating the name.
+The
+.B home\-cluster
+option will change the cluster name as recorded in the superblock and
+bitmap. This option only works for clustered environment.
+
The
.B resync
option will cause the array to be marked
useful if you are certain that the reason for failure has been
resolved.
+.TP
+.B \-\-add\-spare
+Add a device as a spare. This is similar to
+.B \-\-add
+except that it does not attempt
+.B \-\-re\-add
+first. The device will be added as a spare even if it looks like it
+could be an recent member of the array.
+
.TP
.BR \-r ", " \-\-remove
remove listed devices. They must not be active. i.e. they should
.BR \-\-readwrite
Subsequent devices that are added or re\-added will have the 'write-mostly'
flag cleared.
+.TP
+.BR \-\-cluster\-confirm
+Confirm the existence of the device. This is issued in response to an \-\-add
+request by a node in a cluster. When a node adds a device it sends a message
+to all nodes in the cluster to look for a device with a UUID. This translates
+to a udev notification with the UUID of the device to be added and the slot
+number. The receiving node must acknowledge this message
+with \-\-cluster\-confirm. Valid arguments are <slot>:<devicename> in case
+the device is found or <slot>:missing in case the device is not found.
.P
Each of these options requires that the first device listed is the array
.TP
.BR \-Y ", " \-\-export
When used with
-.B \-\-detail , \-\-detail-platform
-or
+.BR \-\-detail ,
+.BR \-\-detail-platform ,
.BR \-\-examine ,
+or
+.B \-\-incremental
output will be formatted as
.B key=value
pairs for easy import into the environment.
+With
+.B \-\-incremental
+The value
+.B MD_STARTED
+indicates whether an array was started
+.RB ( yes )
+or not, which may include a reason
+.RB ( unsafe ", " nothing ", " no ).
+Also the value
+.B MD_FOREIGN
+indicates if the array is expected on this host
+.RB ( no ),
+or seems to be from elsewhere
+.RB ( yes ).
+
.TP
.BR \-E ", " \-\-examine
Print contents of the metadata stored on the named device(s).
kernel handles dirty-clean transitions at shutdown. No action is taken
if safe-mode handling is disabled.
+.TP
+.B \-\-action=
+Set the "sync_action" for all md devices given to one of
+.BR idle ,
+.BR frozen ,
+.BR check ,
+.BR repair .
+Setting to
+.B idle
+will abort any currently running action though some actions will
+automatically restart.
+Setting to
+.B frozen
+will abort any current action and ensure no other action starts
+automatically.
+
+Details of
+.B check
+and
+.B repair
+can be found it
+.IR md (4)
+under
+.BR "SCRUBBING AND MISMATCHES" .
+
.SH For Incremental Assembly mode:
.TP
.BR \-\-rebuild\-map ", " \-r
.B name
is supported.
-The
+The
.B name
option updates the subarray name in the metadata, it may not affect the
device node name or the device node symlink until the subarray is
-re\-assembled. If updating
+re\-assembled. If updating
.B name
would change the UUID of an active subarray this operation is blocked,
and the command will end in an error.
.TP
.B RebuildStarted
-An md array started reconstruction. (syslog priority: Warning)
+An md array started reconstruction (e.g. recovery, resync, reshape,
+check, repair). (syslog priority: Warning)
.TP
.BI Rebuild NN
.RB [ \-\-run ]
.RB [ \-\-quiet ]
.I component-device
+.RI [ optional-aliases-for-device ]
.HP 12
Usage:
.B mdadm \-\-incremental \-\-fail
.B DEVICES
line in that file. If
.B DEVICES
-is absent then the default it to allow any device. Similar if
+is absent then the default it to allow any device. Similarly if
.B DEVICES
contains the special word
.B partitions
then any device is allowed. Otherwise the device name given to
-.I mdadm
+.IR mdadm ,
+or one of the aliases given, or an alias found in the filesystem,
must match one of the names or patterns in a
.B DEVICES
line.
+This is the only context where the aliases are used. They are
+usually provided by a
+.I udev
+rules mentioning
+.BR ${DEVLINKS} .
+
.IP +
Does the device have a valid md superblock? If a specific metadata
version is requested with
.I mdadm
will create and devices that are needed.
+.TP
+.B MDADM_NO_SYSTEMCTL
+If
+.I mdadm
+detects that
+.I systemd
+is in use it will normally request
+.I systemd
+to start various background tasks (particularly
+.IR mdmon )
+rather than forking and running them in the background. This can be
+suppressed by setting
+.BR MDADM_NO_SYSTEMCTL=1 .
+
.TP
.B IMSM_NO_PLATFORM
A key value of IMSM metadata is that it allows interoperability with
recovery. You should be aware that interoperability may be
compromised by setting this value.
+.TP
+.B MDADM_GROW_ALLOW_OLD
+If an array is stopped while it is performing a reshape and that
+reshape was making use of a backup file, then when the array is
+re-assembled
+.I mdadm
+will sometimes complain that the backup file is too old. If this
+happens and you are certain it is the right backup file, you can
+over-ride this check by setting
+.B MDADM_GROW_ALLOW_OLD=1
+in the environment.
+
.TP
.B MDADM_CONF_AUTO
Any string given in this variable is added to the start of the
From kernel version 2.6.28 the "non-partitioned array" can actually
be partitioned. So the "md_d\fBNN\fP"
names are no longer needed, and
-partitions such as "/dev/md\fBNN\fPp\fBXX\fp"
+partitions such as "/dev/md\fBNN\fPp\fBXX\fP"
are possible.
.PP
From kernel version 2.6.29 standard names can be non-numeric following
projects / thirdparty / mdadm.git / blobdiff