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 either of both of the words
64 to look for assembled CONTAINER arrays and included them as a source
65 for assembling further arrays.
73 and include all devices and partitions found therein.
75 does not use the names from
77 but only the major and minor device numbers. It scans
79 to find the name that matches the numbers.
81 If no DEVICE line is present, then "DEVICE partitions containers" is assumed.
85 DEVICE /dev/hda* /dev/hdc*
89 DEVICE /dev/discs/disc*/disc
95 The ARRAY lines identify actual arrays. The second word on the line
96 may be the name of the device where the array is normally
99 If no device name is given,
101 will use various heuristic to determine an appropriate name.
103 Subsequent words identify the array, or identify the array as a member
104 of a group. If multiple identities are given,
105 then a component device must match ALL identities to be considered a
106 match. Each identity word has a tag, and equals sign, and some value.
112 The value should be a 128 bit uuid in hexadecimal, with punctuation
113 interspersed if desired. This must match the uuid stored in the
117 The value should be a simple textual name as was given to
119 when the array was created. This must match the name stored in the
120 superblock on a device for that device to be included in the array.
121 Not all superblock formats support names.
124 The value is an integer which indicates the minor number that was
125 stored in the superblock when the array was created. When an array is
126 created as /dev/mdX, then the minor number X is stored.
129 The value is a comma separated list of device names or device name
131 Only devices with names which match one entry in the list will be used
132 to assemble the array. Note that the devices
133 listed there must also be listed on a DEVICE line.
136 The value is a raid level. This is not normally used to
137 identify an array, but is supported so that the output of
139 .B "mdadm \-\-examine \-\-scan"
141 can be use directly in the configuration file.
144 The value is the number of devices in a complete active array. As with
146 this is mainly for compatibility with the output of
148 .BR "mdadm \-\-examine \-\-scan" .
152 The value is a number of spare devices to expect the array to have.
154 will report an array if it is found to have fewer than this number of
163 The value is a textual name for a group of arrays. All arrays with
166 name are considered to be part of the same group. The significance of
167 a group of arrays is that
169 will, when monitoring the arrays, move a spare drive from one array in
170 a group to another array in that group if the first array had a failed
171 or missing drive but no spare.
175 This option declares to
177 that it should try to create the device file of the array if it
178 doesn't already exist, or exists but with the wrong device number.
180 The value of this option can be "yes" or "md" to indicate that a
181 traditional, non-partitionable md array should be created, or "mdp",
182 "part" or "partition" to indicate that a partitionable md array (only
183 available in linux 2.6 and later) should be used. This later set can
184 also have a number appended to indicate how many partitions to create
185 device files for, e.g.
191 The option specifies a file in which a write-intent bitmap should be
192 found. When assembling the array,
194 will provide this file to the
196 driver as the bitmap file. This has the same function as the
203 Specify the metadata format that the array has. This is mainly
204 recognised for comparability with the output of
209 Specify that this array is a member array of some container. The
210 value given can be either a path name in /dev, or a UUID of the
215 Specify that this array is a member array of some container. Each
216 type of container has some way to enumerate member arrays, often a
217 simple sequence number. The value identifies which member of a
218 container the array is. It will usually accompany a 'container=' word.
225 line gives an E-mail address that alerts should be
230 mode (and was given the
232 option). There should only be one
234 line and it should have only one address.
241 line (which can only be abbreviated to at least 5 characters) gives an
242 address to appear in the "From" address for alert mails. This can be
243 useful if you want to explicitly set a domain, as the default from
244 address is "root" with no domain. All words on this line are
245 catenated with spaces to form the address.
247 Note that this value cannot be set via the
249 commandline. It is only settable via the config file.
255 line gives the name of a program to be run when
256 .B "mdadm \-\-monitor"
257 detects potentially interesting events on any of the arrays that it
258 is monitoring. This program gets run with two or three arguments, they
259 being the Event, the md device, and possibly the related component
262 There should only be one
264 line and it should be give only one program.
271 line gives default values to be used when creating arrays and device entries for
280 These can give user/group ids or names to use instead of system
281 defaults (root/wheel or root/disk).
284 An octal file mode such as 0660 can be given to override the default
288 This corresponds to the
295 \(em possibly followed by a number of partitions \(em to indicate how
296 missing device entries should be created.
300 The name of the metadata format to use if none is explicitly given.
301 This can be useful to impose a system-wide default of version-1 superblocks.
305 Normally when creating devices in
308 will create a matching symlink from
316 to suppress this symlink creation.
323 line gives a default value for the
325 option to mdadm. There should be exactly one other word on the line.
326 It should either exactly
332 .BR gethostname ( 2 )
333 systemcall is used to get the host name.
334 When arrays are created, this host name will be stored in the
335 metadata. When arrays are assembled using auto-assembly, only arrays
336 with this host name stored in the metadata will be considered.
339 DEVICE /dev/sd[bcdjkl]1
341 DEVICE /dev/hda1 /dev/hdb1
343 # /dev/md0 is known by its UUID.
345 ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
347 # /dev/md1 contains all devices with a minor number of
349 # 1 in the superblock.
351 ARRAY /dev/md1 superminor=1
353 # /dev/md2 is made from precisely these two devices
355 ARRAY /dev/md2 devices=/dev/hda1,/dev/hdb1
357 # /dev/md4 and /dev/md5 are a spare-group and spares
359 # can be moved between them
361 ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df
365 ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977
369 # /dev/md/home is created if need to be a partitionable md array
371 # any spare device number is allocated.
373 ARRAY /dev/md/home UUID=9187a482:5dde19d9:eea3cc4a:d646ab8b
377 MAILADDR root@mydomain.tld
379 PROGRAM /usr/sbin/handle\-mdadm\-events
381 CREATE group=system mode=0640 auto=part\-8
projects / thirdparty / mdadm.git / blob