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 Alternatively, a
  49 .B device
  50 line can contain the word
  51 .BR partitions .
  52 This will cause
  53 .I mdadm
  54 to read
  55 .I /proc/partitions
  56 and include all devices and partitions found there-in.
  57 .I mdadm
  58 does not use the names from
  59 .I /proc/partitions
  60 but only the major and minor device numbers.  It scans
  61 .I /dev
  62 to find the name that matches the numbers.
  63
  64 For example:
  65 .IP
  66 DEVICE /dev/hda* /dev/hdc*
  67 .br
  68 DEV    /dev/sd*
  69 .br
  70 DEVICE /dev/discs/disc*/disc
  71 .br
  72 DEVICE partitions
  73
  74 .TP
  75 .B ARRAY
  76 The ARRAY lines identify actual arrays.  The second word on the line
  77 should be the name of the device where the array is normally
  78 assembled, such as
  79 .BR  /dev/md1 .
  80 Subsequent words identify the array, or identify the array as a member
  81 of a group. If multiple identities are given,
  82 then a component device must match ALL identities to be considered a
  83 match.  Each identity word has a tag, and equals sign, and some value.
  84 The tags are:
  85
  86 .RS 4
  87 .TP
  88 .B uuid=
  89 The value should be a 128 bit uuid in hexadecimal, with punctuation
  90 interspersed if desired.  This must match the uuid stored in the
  91 superblock.
  92 .TP
  93 .B super-minor=
  94 The value is an integer which indicates the minor number that was
  95 stored in the superblock when the array was created. When an array is
  96 created as /dev/mdX, then the minor number X is stored.
  97 .TP
  98 .B devices=
  99 The value is a comma separated list of device names. Precisely these
 100 devices will be used to assemble the array.  Note that the devices
 101 listed there must also be listed on a DEVICE line.
 102 .TP
 103 .B level=
 104 The value is a raid level.  This is not normally used to
 105 identify an array, but is supported so that the output of
 106
 107 .B "mdadm --examine --scan"
 108
 109 can be use directly in the configuration file.
 110 .TP
 111 .B num-devices=
 112 The value is the number of devices in a complete active array.  As with
 113 .B level=
 114 this is mainly for compatibility with the output of
 115
 116 .BR "mdadm --examine --scan" .
 117
 118 .TP
 119 .B spare-group=
 120 The value is a textual name for a group of arrays.  All arrays with
 121 the same
 122 .B spare-group
 123 name are considered to be part of the same group.  The significance of
 124 a group of arrays is that
 125 .B mdadm
 126 will, when monitoring the arrays, move a spare drive from one array in
 127 a group to another array in that group if the first array had a failed
 128 or missing drive but no spare.
 129 .RE
 130
 131 .TP
 132 .B MAILADDR
 133 The
 134 .B mailaddr
 135 line gives an E-mail address that alerts should be
 136 sent to when
 137 .M mdadm
 138 is running in
 139 .B --monitor
 140 mode (and was given the
 141 .B --scan
 142 option).  There should only be one
 143 .B MAILADDR
 144 line and it should have only one address.
 145
 146
 147 .TP
 148 .B PROGRAM
 149 The
 150 .B program
 151 line gives the name of a program to be run when
 152 .B "mdadm --monitor"
 153 detects potentially interesting events on any of the arrays that it
 154 is monitoring.  This program gets run with two or three arguments, they
 155 being the Event, the md device, and possibly the related component
 156 device.
 157
 158 There should only be one
 159 .B program
 160 line and it should be give only one program.
 161
 162 .SH EXAMPLE
 163 DEVICE /dev/sd[bcdjkl]1
 164 .br
 165 DEVICE /dev/hda1 /dev/hdb1
 166
 167 # /dev/md0 is known by it's UID.
 168 .br
 169 ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
 170 .br
 171 # /dev/md1 contains all devices with a minor number of
 172 .br
 173 #   1 in the superblock.
 174 .br
 175 ARRAY /dev/md1 superminor=1
 176 .br
 177 # /dev/md2 is made from precisey these two devices
 178 .br
 179 ARRAY /dev/md2 devices=/dev/hda1,/dev/hda2
 180
 181 # /dev/md4 and /dev/md5 are a spare-group and spares
 182 .br
 183 #  can be moved between them
 184 .br
 185 ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df
 186 .br
 187            spare-group=group1
 188 .br
 189 ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977
 190 .br
 191            spare-group=group1
 192
 193 MAILADDR root@mydomain.tld
 194 .br
 195 PROGRAM /usr/sbin/handle-mdadm-events
 196
 197
 198 .SH SEE ALSO
 199 .BR mdadm (8),
 200 .BR md (4).
 201