+.\" Copyright Neil Brown and others.
+.\" This program is free software; you can redistribute it and/or modify
+.\" it under the terms of the GNU General Public License as published by
+.\" 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.CONF 5
.SH NAME
-mdadm.conf \- configuration for management of Software Raid with mdadm
+mdadm.conf \- configuration for management of Software RAID with mdadm
.SH SYNOPSIS
/etc/mdadm.conf
.SH DESCRIPTION
.PP
-.B mdadm
+.I mdadm
is a tool for creating, managing, and monitoring RAID devices using the
.B md
driver in Linux.
line lists the devices (whole devices or partitions) that might contain
a component of an MD array. When looking for the components of an
array,
-.B mdadm
+.I mdadm
will scan these devices (or any devices listed on the command line).
The
Alternatively, a
.B device
-line can contain the word
+line can contain either of both of the words
+.B containers
+and
.BR partitions .
-This will cause
+The word
+.B containers
+will cause
+.I mdadm
+to look for assembled CONTAINER arrays and included them as a source
+for assembling further arrays.
+.PP
+The word
+.I partitions
+will cause
.I mdadm
to read
.I /proc/partitions
-and include all devices and partitions found there-in.
+and include all devices and partitions found therein.
.I mdadm
does not use the names from
.I /proc/partitions
.I /dev
to find the name that matches the numbers.
+If no DEVICE line is present, then "DEVICE partitions containers" is assumed.
+
For example:
.IP
DEVICE /dev/hda* /dev/hdc*
.TP
.B ARRAY
The ARRAY lines identify actual arrays. The second word on the line
-should be the name of the device where the array is normally
+may be the name of the device where the array is normally
assembled, such as
.BR /dev/md1 .
+If no device name is given,
+.I mdadm
+will use various heuristic to determine an appropriate name.
+.PP
Subsequent words identify the array, or identify the array as a member
of a group. If multiple identities are given,
then a component device must match ALL identities to be considered a
.I mdadm
when the array was created. This must match the name stored in the
superblock on a device for that device to be included in the array.
-Not all superblock-formats support names.
+Not all superblock formats support names.
.TP
-.B super-minor=
+.B super\-minor=
The value is an integer which indicates the minor number that was
stored in the superblock when the array was created. When an array is
created as /dev/mdX, then the minor number X is stored.
The value is a raid level. This is not normally used to
identify an array, but is supported so that the output of
-.B "mdadm --examine --scan"
+.B "mdadm \-\-examine \-\-scan"
can be use directly in the configuration file.
.TP
-.B num-devices=
+.B num\-devices=
The value is the number of devices in a complete active array. As with
.B level=
this is mainly for compatibility with the output of
-.BR "mdadm --examine --scan" .
+.BR "mdadm \-\-examine \-\-scan" .
.TP
-.B spare-group=
+.B spares=
+The value is a number of spare devices to expect the array to have.
+.B mdadm \-\-monitor
+will report an array if it is found to have fewer than this number of
+spares when
+.B \-\-monitor
+starts or when
+.B \-\-oneshot
+is used.
+
+.TP
+.B spare\-group=
The value is a textual name for a group of arrays. All arrays with
the same
-.B spare-group
+.B spare\-group
name are considered to be part of the same group. The significance of
a group of arrays is that
-.B mdadm
+.I mdadm
will, when monitoring the arrays, move a spare drive from one array in
a group to another array in that group if the first array had a failed
or missing drive but no spare.
.TP
.B auto=
This option declares to
-.B mdadm
+.I mdadm
that it should try to create the device file of the array if it
doesn't already exist, or exists but with the wrong device number.
device files for, e.g.
.BR auto=mdp5 .
The default is 4.
+
+.TP
+.B bitmap=
+The option specifies a file in which a write-intent bitmap should be
+found. When assembling the array,
+.I mdadm
+will provide this file to the
+.B md
+driver as the bitmap file. This has the same function as the
+.B \-\-bitmap\-file
+option to
+.BR \-\-assemble .
+
+.TP
+.B metadata=
+Specify the metadata format that the array has. This is mainly
+recognised for comparability with the output of
+.BR "mdadm \-Es" .
+
+.TP
+.B container=
+Specify that this array is a member array of some container. The
+value given can be either a path name in /dev, or a UUID of the
+container array.
+
+.IP
+.B member=
+Specify that this array is a member array of some container. Each
+type of container has some way to enumerate member arrays, often a
+simple sequence number. The value identifies which member of a
+container the array is. It will usually accompany a 'container=' word.
.RE
.TP
.B mailaddr
line gives an E-mail address that alerts should be
sent to when
-.M mdadm
+.I mdadm
is running in
-.B --monitor
+.B \-\-monitor
mode (and was given the
-.B --scan
+.B \-\-scan
option). There should only be one
.B MAILADDR
line and it should have only one address.
+.TP
+.B MAILFROM
+The
+.B mailfrom
+line (which can only be abbreviated to at least 5 characters) gives an
+address to appear in the "From" address for alert mails. This can be
+useful if you want to explicitly set a domain, as the default from
+address is "root" with no domain. All words on this line are
+catenated with spaces to form the address.
+
+Note that this value cannot be set via the
+.I mdadm
+commandline. It is only settable via the config file.
+
.TP
.B PROGRAM
The
.B program
line gives the name of a program to be run when
-.B "mdadm --monitor"
+.B "mdadm \-\-monitor"
detects potentially interesting events on any of the arrays that it
is monitoring. This program gets run with two or three arguments, they
being the Event, the md device, and possibly the related component
.B program
line and it should be give only one program.
+
+.TP
+.B CREATE
+The
+.B create
+line gives default values to be used when creating arrays and device entries for
+arrays.
+These include:
+
+.RS 4
+.TP
+.B owner=
+.TP
+.B group=
+These can give user/group ids or names to use instead of system
+defaults (root/wheel or root/disk).
+.TP
+.B mode=
+An octal file mode such as 0660 can be given to override the default
+of 0600.
+.TP
+.B auto=
+This corresponds to the
+.B \-\-auto
+flag to mdadm. Give
+.BR yes ,
+.BR md ,
+.BR mdp ,
+.B part
+\(em possibly followed by a number of partitions \(em to indicate how
+missing device entries should be created.
+
+.TP
+.B metadata=
+The name of the metadata format to use if none is explicitly given.
+This can be useful to impose a system-wide default of version-1 superblocks.
+
+.TP
+.B symlinks=no
+Normally when creating devices in
+.B /dev/md/
+.I mdadm
+will create a matching symlink from
+.B /dev/
+with a name starting
+.B md
+or
+.BR md_ .
+Give
+.B symlinks=no
+to suppress this symlink creation.
+.RE
+
+.TP
+.B HOMEHOST
+The
+.B homehost
+line gives a default value for the
+.B --homehost=
+option to mdadm. There should be exactly one other word on the line.
+It should either exactly
+.B <system>
+or a host name.
+If
+.B <system>
+is given, then the
+.BR gethostname ( 2 )
+systemcall is used to get the host name.
+When arrays are created, this host name will be stored in the
+metadata. When arrays are assembled using auto-assembly, only arrays
+with this host name stored in the metadata will be considered.
+
.SH EXAMPLE
DEVICE /dev/sd[bcdjkl]1
.br
DEVICE /dev/hda1 /dev/hdb1
-# /dev/md0 is known by it's UID.
+# /dev/md0 is known by its UID.
.br
ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
.br
.br
ARRAY /dev/md1 superminor=1
.br
-# /dev/md2 is made from precisey these two devices
+# /dev/md2 is made from precisely these two devices
.br
-ARRAY /dev/md2 devices=/dev/hda1,/dev/hda2
+ARRAY /dev/md2 devices=/dev/hda1,/dev/hdb1
# /dev/md4 and /dev/md5 are a spare-group and spares
.br
.br
ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df
.br
- spare-group=group1
+ spare\-group=group1
.br
ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977
.br
- spare-group=group1
+ spare\-group=group1
.br
# /dev/md/home is created if need to be a partitionable md array
.br
MAILADDR root@mydomain.tld
.br
-PROGRAM /usr/sbin/handle-mdadm-events
-
+PROGRAM /usr/sbin/handle\-mdadm\-events
+.br
+CREATE group=system mode=0640 auto=part\-8
+.br
+HOMEHOST <system>
.SH SEE ALSO
.BR mdadm (8),
projects / thirdparty / mdadm.git / blobdiff