.\" 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 "" v4.2
+.TH MDADM 8 "" v4.3
.SH NAME
mdadm \- manage MD devices
.I aka
which is managed in a similar manner to DDF, and is supported by an
option-rom on some platforms:
.IP
-.B https://www.intel.com/content/www/us/en/support/products/122484/memory-and-storage/ssd-software/intel-virtual-raid-on-cpu-intel-vroc.html
+.B https://www.intel.com/content/www/us/en/support/products/122484
.PP
.RE
.BR \-N ", " \-\-name=
Set a
.B name
-for the array. This is currently only effective when creating an
-array with a version-1 superblock, or an array in a DDF container.
-The name is a simple textual string that can be used to identify array
-components when assembling. If name is needed but not specified, it
-is taken from the basename of the device that is being created.
-e.g. when creating
-.I /dev/md/home
-the
-.B name
-will default to
-.IR home .
+for the array. It must be
+.BR "POSIX PORTABLE NAME"
+compatible and cannot be longer than 32 chars. This is effective when creating an array
+with a v1 metadata, or an external array.
+
+If name is needed but not specified, it is taken from the basename of the device
+that is being created. See
+.BR "DEVICE NAMES"
.TP
.BR \-R ", " \-\-run
.TP
.BR \-N ", " \-\-name=
-Specify the name of the array to assemble. This must be the name
-that was specified when creating the array. It must either match
+Specify the name of the array to assemble. It must be
+.BR "POSIX PORTABLE NAME"
+compatible and cannot be longer than 32 chars. This must be the name
+that was specified when creating the array. It must either match
the name stored in the superblock exactly, or it must match
with the current
.I homehost
.I md-device
.BI \-\-chunk= X
.BI \-\-level= Y
-.br
.BI \-\-raid\-devices= Z
.I devices
.PP
-This usage will initialise a new md array, associate some devices with
+This usage will initialize a new md array, associate some devices with
it, and activate the array.
+.I md-device
+is a new device. This could be standard name or chosen name. For details see:
+.BR "DEVICE NAMES"
+
The named device will normally not exist when
.I "mdadm \-\-create"
is run, but will be created by
.B \-\-force
option.
-When creating an array with version-1 metadata a name for the array is
-required.
-If this is not given with the
-.B \-\-name
-option,
-.I mdadm
-will choose a name based on the last component of the name of the
-device being created. So if
-.B /dev/md3
-is being created, then the name
-.B 3
-will be chosen.
-If
-.B /dev/md/home
-is being created, then the name
-.B home
-will be used.
-
When creating a partition based array, using
.I mdadm
with version-1.x metadata, the partition type should be set to
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
-.B name
-would change the UUID of an active subarray this operation is blocked,
-and the command will end in an error.
+option updates the subarray name in the metadata. It must be
+.BR "POSIX PORTABLE NAME"
+compatible and cannot be longer than 32 chars. If successes, new value will be respected after
+next assembly.
The
.B ppl
recovery. You should be aware that interoperability may be
compromised by setting this value.
-These change can also be suppressed by adding
+These change can also be suppressed by adding
.B mdadm.imsm.test=1
to the kernel command line. This makes it easy to test IMSM
code in a virtual machine that doesn't have IMSM virtual hardware.
.B \-\-incremental
mode is used, this file gets a list of arrays currently being created.
+.SH POSIX PORTABLE NAME
+A valid name can only consist of characters "A-Za-z0-9.-_".
+The name cannot start with a leading "-" and cannot exceed 255 chars.
+
.SH DEVICE NAMES
.I mdadm
.I home
can be given.
+In every style, raw name must be compatible with
+.BR "POSIX PORTABLE NAME"
+and has to be no longer than 32 chars.
+
When
.I mdadm
chooses device names during auto-assembly or incremental assembly, it
since version 3.3 provided they are enabled in
.IR mdadm.conf .
+.SH UNDERSTANDING OUTPUT
+
+.TP
+EXAMINE
+
+.TP
+.B checkpoint
+Checkpoint value is reported when array is performing some action including
+resync, recovery or reshape. Checkpoints allow resuming action from certain
+point if it was interrupted.
+
+Checkpoint is reported as combination of two values: current migration unit
+and number of blocks per unit. By multiplying those values and dividing by
+array size checkpoint progress percentage can be obtained in relation to
+current progress reported in /proc/mdstat. Checkpoint is also related to (and
+sometimes based on) sysfs entry sync_completed but depending on action units
+may differ. Even if units are the same, it should not be expected that
+checkpoint and sync_completed will be exact match nor updated simultaneously.
+
.SH NOTE
.I mdadm
was previously known as
projects / thirdparty / mdadm.git / blobdiff