3 mdadm.conf \- configuration for management of Software Raid with mdadm
9 is a tool for creating, managing, and monitoring RAID devices using the
13 Some common tasks, such as assembling all arrays, can be simplified
14 by describing the devices and arrays in this configuration file.
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.
22 Any line that starts with white space (space or tab) is treated as
23 though it were a continuation of the previous line.
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.
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
38 will scan these devices (or any devices listed on the command line).
42 line may contain a number of different devices (separated by spaces)
43 and each device name can contain wild cards as defined by
46 Also, there may be several device lines present in the file.
50 line can contain the word
56 and include all devices and partitions found there-in.
58 does not use the names from
60 but only the major and minor device numbers. It scans
62 to find the name that matches the numbers.
64 If no DEVICE line is present, then "DEVICE partitions" is assumed.
68 DEVICE /dev/hda* /dev/hdc*
72 DEVICE /dev/discs/disc*/disc
78 The ARRAY lines identify actual arrays. The second word on the line
79 should be the name of the device where the array is normally
82 Subsequent words identify the array, or identify the array as a member
83 of a group. If multiple identities are given,
84 then a component device must match ALL identities to be considered a
85 match. Each identity word has a tag, and equals sign, and some value.
91 The value should be a 128 bit uuid in hexadecimal, with punctuation
92 interspersed if desired. This must match the uuid stored in the
96 The value should be a simple textual name as was given to
98 when the array was created. This must match the name stored in the
99 superblock on a device for that device to be included in the array.
100 Not all superblock-formats support names.
103 The value is an integer which indicates the minor number that was
104 stored in the superblock when the array was created. When an array is
105 created as /dev/mdX, then the minor number X is stored.
108 The value is a comma separated list of device names or device name
110 Only devices with names which match one entry in the list will be used
111 to assemble the array. Note that the devices
112 listed there must also be listed on a DEVICE line.
115 The value is a raid level. This is not normally used to
116 identify an array, but is supported so that the output of
118 .B "mdadm --examine --scan"
120 can be use directly in the configuration file.
123 The value is the number of devices in a complete active array. As with
125 this is mainly for compatibility with the output of
127 .BR "mdadm --examine --scan" .
131 The value is a textual name for a group of arrays. All arrays with
134 name are considered to be part of the same group. The significance of
135 a group of arrays is that
137 will, when monitoring the arrays, move a spare drive from one array in
138 a group to another array in that group if the first array had a failed
139 or missing drive but no spare.
143 This option declares to
145 that it should try to create the device file of the array if it
146 doesn't already exist, or exists but with the wrong device number.
148 The value of this option can be "yes" or "md" to indicate that a
149 traditional, non-partitionable md array should be created, or "mdp",
150 "part" or "partition" to indicate that a partitionable md array (only
151 available in linux 2.6 and later) should be used. This later set can
152 also have a number appended to indicate how many partitions to create
153 device files for, e.g.
159 The option specifies a file in which a write-intent bitmap should be
160 found. When assembling the array,
162 will provide this file to the
164 driver as the bitmap file. This has the same function as the
174 line gives an E-mail address that alerts should be
179 mode (and was given the
181 option). There should only be one
183 line and it should have only one address.
190 line (which can only be abbreviate at leat 5 characters) gives an
191 address to appear in the "From" address for alert mails. This can be
192 useful if you want to explicitly set a domain, as the default from
193 address is "root" with no domain. All words on this line are
194 catenated with spaces to form the address.
196 Note that this value cannot be set via the
198 commandline. It is only settable via the config file.
204 line gives the name of a program to be run when
206 detects potentially interesting events on any of the arrays that it
207 is monitoring. This program gets run with two or three arguments, they
208 being the Event, the md device, and possibly the related component
211 There should only be one
213 line and it should be give only one program.
220 line gives default values to be used when creating device entries for
229 These can give user/group ids or names to use instead of system
230 defaults (root/wheel or root/disk).
233 An octal file mode such as 0660 can be given to override the default
237 This corresponds to the
244 - possibly followed by a number of partitions - to indicate how
245 missing device entries should be created.
251 DEVICE /dev/sd[bcdjkl]1
253 DEVICE /dev/hda1 /dev/hdb1
255 # /dev/md0 is known by it's UID.
257 ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
259 # /dev/md1 contains all devices with a minor number of
261 # 1 in the superblock.
263 ARRAY /dev/md1 superminor=1
265 # /dev/md2 is made from precisey these two devices
267 ARRAY /dev/md2 devices=/dev/hda1,/dev/hdb1
269 # /dev/md4 and /dev/md5 are a spare-group and spares
271 # can be moved between them
273 ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df
277 ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977
281 # /dev/md/home is created if need to be a partitionable md array
283 # any spare device number is allocated.
285 ARRAY /dev/md/home UUID=9187a482:5dde19d9:eea3cc4a:d646ab8b
289 MAILADDR root@mydomain.tld
291 PROGRAM /usr/sbin/handle-mdadm-events
293 CREATE group=system mode=0640 auto=part-8
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