If a device is given before any options, or if the first option is
.BR \-\-add ,
.BR \-\-fail ,
-or
.BR \-\-remove ,
+or
+.BR \-\-replace ,
then the MANAGE mode is assumed.
Anything other than these will cause the
.B Misc
.IP "0, 0.90, default"
.el
.IP "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
.IP "1, 1.0, 1.1, 1.2"
.el
.IP "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
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.
+
+When creating an array,
+.B \-\-data\-offset
+can be specified as
+.BR variable .
+In the case each member device is expected to have a offset appended
+to the name, separated by a colon. This makes it possible to recreate
+exactly an array which has varying data offsets (as can happen when
+different versions of
+.I mdadm
+are used to add different devices).
+
.TP
.BR \-\-continue
This option is complementary to the
or
.BR \-\-build .
-.ig XX
-.\".TP
-.\".BR \-\-symlink = no
-.\"Normally when
-.\".B \-\-auto
-.\"causes
-.\".I mdadm
-.\"to create devices in
-.\".B /dev/md/
-.\"it will also create symlinks from
-.\".B /dev/
-.\"with names starting with
-.\".B md
-.\"or
-.\".BR md_ .
-.\"Use
-.\".B \-\-symlink=no
-.\"to suppress this, or
-.\".B \-\-symlink=yes
-.\"to enforce this even if it is suppressing
-.\".IR mdadm.conf .
-.\"
-.XX
-
.TP
.BR \-a ", " "\-\-add"
This option can be used in Grow mode in two cases.
.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.
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 \-f ", " \-\-fail
-mark listed devices as faulty.
+Mark listed devices as faulty.
As well as the name of a device file, the word
.B detached
can be given. This will cause any device that has been detached from
same as
.BR \-\-fail .
+.TP
+.B \-\-replace
+Mark listed devices as requiring replacement. As soon as a spare is
+available, it will be rebuilt and will replace the marked device.
+This is similar to marking a device as faulty, but the device remains
+in service during the recovery process to increase resilience against
+multiple failures. When the replacement process finishes, the
+replaced device will be marked as faulty.
+
+.TP
+.B \-\-with
+This can follow a list of
+.B \-\-replace
+devices. The devices listed after
+.B \-\-with
+will be preferentially used to replace the devices listed after
+.BR \-\-replace .
+These device must already be spare devices in the array.
+
.TP
.BR \-\-write\-mostly
Subsequent devices that are added or re\-added will have the 'write-mostly'
.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
projects / thirdparty / mdadm.git / blobdiff