1 .\" Copyright Neil Brown and others.
2 .\" This program is free software; you can redistribute it and/or modify
3 .\" it under the terms of the GNU General Public License as published by
4 .\" the Free Software Foundation; either version 2 of the License, or
5 .\" (at your option) any later version.
6 .\" See file COPYING in distribution for details.
9 mdadm.conf \- configuration for management of Software RAID with mdadm
15 is a tool for creating, managing, and monitoring RAID devices using the
19 Some common tasks, such as assembling all arrays, can be simplified
20 by describing the devices and arrays in this configuration file.
23 The file should be seen as a collection of words separated by white
24 space (space, tab, or newline).
25 Any word that beings with a hash sign (#) starts a comment and that
26 word together with the remainder of the line is ignored.
28 Any line that starts with white space (space or tab) is treated as
29 though it were a continuation of the previous line.
31 Empty lines are ignored, but otherwise each (non continuation) line
32 must start with a keyword as listed below. The keywords are case
33 insensitive and can be abbreviated to 3 characters.
40 line lists the devices (whole devices or partitions) that might contain
41 a component of an MD array. When looking for the components of an
44 will scan these devices (or any devices listed on the command line).
48 line may contain a number of different devices (separated by spaces)
49 and each device name can contain wild cards as defined by
52 Also, there may be several device lines present in the file.
56 line can contain the word
62 and include all devices and partitions found therein.
64 does not use the names from
66 but only the major and minor device numbers. It scans
68 to find the name that matches the numbers.
70 If no DEVICE line is present, then "DEVICE partitions" is assumed.
74 DEVICE /dev/hda* /dev/hdc*
78 DEVICE /dev/discs/disc*/disc
84 The ARRAY lines identify actual arrays. The second word on the line
85 should be the name of the device where the array is normally
88 Subsequent words identify the array, or identify the array as a member
89 of a group. If multiple identities are given,
90 then a component device must match ALL identities to be considered a
91 match. Each identity word has a tag, and equals sign, and some value.
97 The value should be a 128 bit uuid in hexadecimal, with punctuation
98 interspersed if desired. This must match the uuid stored in the
102 The value should be a simple textual name as was given to
104 when the array was created. This must match the name stored in the
105 superblock on a device for that device to be included in the array.
106 Not all superblock formats support names.
109 The value is an integer which indicates the minor number that was
110 stored in the superblock when the array was created. When an array is
111 created as /dev/mdX, then the minor number X is stored.
114 The value is a comma separated list of device names or device name
116 Only devices with names which match one entry in the list will be used
117 to assemble the array. Note that the devices
118 listed there must also be listed on a DEVICE line.
121 The value is a raid level. This is not normally used to
122 identify an array, but is supported so that the output of
124 .B "mdadm \-\-examine \-\-scan"
126 can be use directly in the configuration file.
129 The value is the number of devices in a complete active array. As with
131 this is mainly for compatibility with the output of
133 .BR "mdadm \-\-examine \-\-scan" .
137 The value is a number of spare devices to expect the array to have.
139 will report an array if it is found to have fewer than this number of
148 The value is a textual name for a group of arrays. All arrays with
151 name are considered to be part of the same group. The significance of
152 a group of arrays is that
154 will, when monitoring the arrays, move a spare drive from one array in
155 a group to another array in that group if the first array had a failed
156 or missing drive but no spare.
160 This option declares to
162 that it should try to create the device file of the array if it
163 doesn't already exist, or exists but with the wrong device number.
165 The value of this option can be "yes" or "md" to indicate that a
166 traditional, non-partitionable md array should be created, or "mdp",
167 "part" or "partition" to indicate that a partitionable md array (only
168 available in linux 2.6 and later) should be used. This later set can
169 also have a number appended to indicate how many partitions to create
170 device files for, e.g.
176 The option specifies a file in which a write-intent bitmap should be
177 found. When assembling the array,
179 will provide this file to the
181 driver as the bitmap file. This has the same function as the
188 Specify the metadata format that the array has. This is mainly
189 recognised for comparability with the output of
198 line gives an E-mail address that alerts should be
203 mode (and was given the
205 option). There should only be one
207 line and it should have only one address.
214 line (which can only be abbreviated to at least 5 characters) gives an
215 address to appear in the "From" address for alert mails. This can be
216 useful if you want to explicitly set a domain, as the default from
217 address is "root" with no domain. All words on this line are
218 catenated with spaces to form the address.
220 Note that this value cannot be set via the
222 commandline. It is only settable via the config file.
228 line gives the name of a program to be run when
229 .B "mdadm \-\-monitor"
230 detects potentially interesting events on any of the arrays that it
231 is monitoring. This program gets run with two or three arguments, they
232 being the Event, the md device, and possibly the related component
235 There should only be one
237 line and it should be give only one program.
244 line gives default values to be used when creating arrays and device entries for
253 These can give user/group ids or names to use instead of system
254 defaults (root/wheel or root/disk).
257 An octal file mode such as 0660 can be given to override the default
261 This corresponds to the
268 \(em possibly followed by a number of partitions \(em to indicate how
269 missing device entries should be created.
273 The name of the metadata format to use if none is explicitly given.
274 This can be useful to impose a system-wide default of version-1 superblocks.
278 Normally when creating devices in
281 will create a matching symlink from
289 to suppress this symlink creation.
294 DEVICE /dev/sd[bcdjkl]1
296 DEVICE /dev/hda1 /dev/hdb1
298 # /dev/md0 is known by its UID.
300 ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
302 # /dev/md1 contains all devices with a minor number of
304 # 1 in the superblock.
306 ARRAY /dev/md1 superminor=1
308 # /dev/md2 is made from precisely these two devices
310 ARRAY /dev/md2 devices=/dev/hda1,/dev/hdb1
312 # /dev/md4 and /dev/md5 are a spare-group and spares
314 # can be moved between them
316 ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df
320 ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977
324 # /dev/md/home is created if need to be a partitionable md array
326 # any spare device number is allocated.
328 ARRAY /dev/md/home UUID=9187a482:5dde19d9:eea3cc4a:d646ab8b
332 MAILADDR root@mydomain.tld
334 PROGRAM /usr/sbin/handle\-mdadm\-events
336 CREATE group=system mode=0640 auto=part\-8
projects / thirdparty / mdadm.git / blob