mdadm.conf.5

   1 .TH MDADM.CONF 5
   2 .SH NAME
   3 mdadm.conf \- configuration for management of Software Raid with mdadm
   4 .SH SYNOPSIS
   5 /etc/mdadm.conf
   6 .SH DESCRIPTION
   7 .PP
   8 .B mdadm
   9 is a tool for creating, managing, and monitoring RAID devices using the
  10 .B md
  11 driver in Linux.
  12 .PP
  13 Some common tasks, such as assembling all arrays, can be simplified
  14 by describing the devices and arrays in this configuration file.
  15
  16 .SS SYNTAX
  17 The file should be seen as a collection of words separated by white
  18 space (space, tab, or newline).
  19 Any word that beings with a hash sign (#) starts a comment and that
  20 word together with the remainder of the line is ignored.
  21
  22 Any line that starts with white space (space or tab) is treated as
  23 though it were a continuation of the previous line.
  24
  25 Empty lines are ignored, but otherwise each (non continuation) line
  26 must start with a keyword as listed below.  The keywords are case
  27 insensitive and can be abbreviated to 3 characters.
  28
  29 The keywords are:
  30 .TP
  31 .B DEVICE
  32 A
  33 .B device
  34 line lists the devices (whole devices or partitions) that might contain
  35 a component of an MD array.  When looking for the components of an
  36 array,
  37 .B mdadm
  38 will scan these devices (or any devices listed on the command line).
  39
  40 The
  41 .B device
  42 line may contain a number of different devices (separated by spaces)
  43 and each device name can contain wild cards as defined by
  44 .BR glob (7).
  45
  46 Also, there may be several device lines present in the file.
  47
  48 For example:
  49 .IP
  50 DEVICE /dev/hda* /dev/hdc*
  51 .br
  52 DEV    /dev/sd*
  53 .br
  54 DEVICE /dev/discs/disc*/disc
  55
  56 .TP
  57 .B ARRAY
  58 The ARRAY lines identify actual arrays.  The second word on the line
  59 should be the name of the device where the array is normally
  60 assembled, such as
  61 .BR  /dev/md1 .
  62 Subsequent words identify the array, or identify the array as a member
  63 of a group. If multiple identities are given,
  64 then a component device must match ALL identities to be considered a
  65 match.  Each identity word has a tag, and equals sign, and some value.
  66 The tags are:
  67
  68 .RS 4
  69 .TP
  70 .B uuid=
  71 The value should be a 128 bit uuid in hexadecimal, with punctuation
  72 interspersed if desired.  This must match the uuid stored in the
  73 superblock.
  74 .TP
  75 .B super-minor=
  76 The value is an integer which indicates the minor number that was
  77 stored in the superblock when the array was created. When an array is
  78 created as /dev/mdX, then the minor number X is stored.
  79 .TP
  80 .B devices=
  81 The value is a comma separated list of device names. Precisely these
  82 devices will be used to assemble the array.  Note that the devices
  83 listed there must also be listed on a DEVICE line.
  84 .TP
  85 .B level=
  86 The value is a raid level.  This is not normally used to
  87 identify an array, but is supported so that the output of
  88
  89 .B "mdadm --examine --scan"
  90
  91 can be use directly in the configuration file.
  92 .TP
  93 .B num-devices=
  94 The value is the number of devices in a complete active array.  As with
  95 .B level=
  96 this is mainly for compatibility with the output of
  97
  98 .BR "mdadm --examine --scan" .
  99
 100 .TP
 101 .B spare-group=
 102 The value is a textual name for a group of arrays.  All arrays with
 103 the same
 104 .B spare-group
 105 name are considered to be part of the same group.  The significance of
 106 a group of arrays is that
 107 .B mdadm
 108 will, when monitoring the arrays, move a spare drive from one array in
 109 a group to another array in that group if the first array had a failed
 110 or missing drive but no spare.
 111 .RE
 112
 113 .TP
 114 .B MAILADDR
 115 The
 116 .B mailaddr
 117 line gives an E-mail address that alerts should be
 118 sent to when
 119 .M mdadm
 120 is running in
 121 .B --monitor
 122 mode (and was given the
 123 .B --scan
 124 option).  There should only be one
 125 .B MAILADDR
 126 line and it should have only one address.
 127
 128
 129 .TP
 130 .B PROGRAM
 131 The
 132 .B program
 133 line gives the name of a program to be run when
 134 .B "mdadm --monitor"
 135 detects potentially interesting events on any of the arrays that it
 136 is monitoring.  This program gets run with two or three arguments, they
 137 being the Event, the md device, and possibly the related component
 138 device.
 139
 140 There should only be one
 141 .B program
 142 line and it should be give only one program.
 143
 144 .SH EXAMPLE
 145 DEVICE /dev/sd[bcdjkl]1
 146 .br
 147 DEVICE /dev/hda1 /dev/hdb1
 148
 149 # /dev/md0 is known by it's UID.
 150 .br
 151 ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
 152 .br
 153 # /dev/md1 contains all devices with a minor number of
 154 .br
 155 #   1 in the superblock.
 156 .br
 157 ARRAY /dev/md1 superminor=1
 158 .br
 159 # /dev/md2 is made from precisey these two devices
 160 .br
 161 ARRAY /dev/md2 devices=/dev/hda1,/dev/hda2
 162
 163 # /dev/md4 and /dev/md5 are a spare-group and spares
 164 .br
 165 #  can be moved between them
 166 .br
 167 ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df
 168 .br
 169            spare-group=group1
 170 .br
 171 ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977
 172 .br
 173            spare-group=group1
 174
 175 MAILADDR root@mydomain.tld
 176 .br
 177 PROGRAM /usr/sbin/handle-mdadm-events
 178
 179
 180 .SH SEE ALSO
 181 .BR mdadm (8),
 182 .BR md (4).
 183