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519561f7 NB |
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. | |
56eb10c0 NB |
7 | .TH MDADM.CONF 5 |
8 | .SH NAME | |
93e790af | 9 | mdadm.conf \- configuration for management of Software RAID with mdadm |
56eb10c0 NB |
10 | .SH SYNOPSIS |
11 | /etc/mdadm.conf | |
12 | .SH DESCRIPTION | |
13 | .PP | |
14 | .B mdadm | |
11a3e71d | 15 | is a tool for creating, managing, and monitoring RAID devices using the |
56eb10c0 NB |
16 | .B md |
17 | driver in Linux. | |
18 | .PP | |
19 | Some common tasks, such as assembling all arrays, can be simplified | |
2d465520 | 20 | by describing the devices and arrays in this configuration file. |
56eb10c0 NB |
21 | |
22 | .SS SYNTAX | |
23 | The file should be seen as a collection of words separated by white | |
24 | space (space, tab, or newline). | |
11a3e71d | 25 | Any word that beings with a hash sign (#) starts a comment and that |
2d465520 | 26 | word together with the remainder of the line is ignored. |
56eb10c0 | 27 | |
2d465520 | 28 | Any line that starts with white space (space or tab) is treated as |
56eb10c0 NB |
29 | though it were a continuation of the previous line. |
30 | ||
31 | Empty lines are ignored, but otherwise each (non continuation) line | |
2d465520 | 32 | must start with a keyword as listed below. The keywords are case |
e0d19036 | 33 | insensitive and can be abbreviated to 3 characters. |
56eb10c0 NB |
34 | |
35 | The keywords are: | |
36 | .TP | |
37 | .B DEVICE | |
38 | A | |
39 | .B device | |
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 | |
42 | array, | |
43 | .B mdadm | |
2d465520 | 44 | will scan these devices (or any devices listed on the command line). |
56eb10c0 NB |
45 | |
46 | The | |
47 | .B device | |
48 | line may contain a number of different devices (separated by spaces) | |
49 | and each device name can contain wild cards as defined by | |
50 | .BR glob (7). | |
51 | ||
52 | Also, there may be several device lines present in the file. | |
53 | ||
5787fa49 NB |
54 | Alternatively, a |
55 | .B device | |
56 | line can contain the word | |
57 | .BR partitions . | |
58 | This will cause | |
59 | .I mdadm | |
60 | to read | |
61 | .I /proc/partitions | |
35cc5be4 | 62 | and include all devices and partitions found therein. |
5787fa49 NB |
63 | .I mdadm |
64 | does not use the names from | |
65 | .I /proc/partitions | |
66 | but only the major and minor device numbers. It scans | |
67 | .I /dev | |
68 | to find the name that matches the numbers. | |
69 | ||
a99d6b66 NB |
70 | If no DEVICE line is present, then "DEVICE partitions" is assumed. |
71 | ||
11a3e71d NB |
72 | For example: |
73 | .IP | |
74 | DEVICE /dev/hda* /dev/hdc* | |
75 | .br | |
76 | DEV /dev/sd* | |
77 | .br | |
78 | DEVICE /dev/discs/disc*/disc | |
5787fa49 NB |
79 | .br |
80 | DEVICE partitions | |
11a3e71d | 81 | |
56eb10c0 NB |
82 | .TP |
83 | .B ARRAY | |
11a3e71d NB |
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 | |
86 | assembled, such as | |
87 | .BR /dev/md1 . | |
e0d19036 NB |
88 | Subsequent words identify the array, or identify the array as a member |
89 | of a group. If multiple identities are given, | |
2d465520 NB |
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. | |
92 | The tags are: | |
11a3e71d NB |
93 | |
94 | .RS 4 | |
95 | .TP | |
96 | .B uuid= | |
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 | |
99 | superblock. | |
100 | .TP | |
947fd4dd NB |
101 | .B name= |
102 | The value should be a simple textual name as was given to | |
103 | .I mdadm | |
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. | |
35cc5be4 | 106 | Not all superblock formats support names. |
947fd4dd | 107 | .TP |
7e23fc43 | 108 | .B super\-minor= |
11a3e71d NB |
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. | |
112 | .TP | |
113 | .B devices= | |
56eedc1a NB |
114 | The value is a comma separated list of device names or device name |
115 | patterns. | |
116 | Only devices with names which match one entry in the list will be used | |
117 | to assemble the array. Note that the devices | |
11a3e71d NB |
118 | listed there must also be listed on a DEVICE line. |
119 | .TP | |
120 | .B level= | |
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 | |
123 | ||
7e23fc43 | 124 | .B "mdadm \-\-examine \-\-scan" |
11a3e71d NB |
125 | |
126 | can be use directly in the configuration file. | |
127 | .TP | |
7e23fc43 | 128 | .B num\-devices= |
b83d95f3 | 129 | The value is the number of devices in a complete active array. As with |
11a3e71d NB |
130 | .B level= |
131 | this is mainly for compatibility with the output of | |
56eb10c0 | 132 | |
7e23fc43 | 133 | .BR "mdadm \-\-examine \-\-scan" . |
e0d19036 | 134 | |
058574b1 NB |
135 | .TP |
136 | .B spares= | |
137 | The value is a number of spare devices to expect the array to have. | |
7e23fc43 | 138 | .B mdadm \-\-monitor |
058574b1 NB |
139 | will report an array if it is found to have fewer than this number of |
140 | spares when | |
7e23fc43 | 141 | .B \-\-monitor |
058574b1 | 142 | starts or when |
7e23fc43 | 143 | .B \-\-oneshot |
058574b1 NB |
144 | is used. |
145 | ||
e0d19036 | 146 | .TP |
7e23fc43 | 147 | .B spare\-group= |
e0d19036 NB |
148 | The value is a textual name for a group of arrays. All arrays with |
149 | the same | |
7e23fc43 | 150 | .B spare\-group |
e0d19036 NB |
151 | name are considered to be part of the same group. The significance of |
152 | a group of arrays is that | |
153 | .B mdadm | |
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. | |
dd0781e5 NB |
157 | |
158 | .TP | |
159 | .B auto= | |
160 | This option declares to | |
161 | .B mdadm | |
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. | |
164 | ||
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. | |
171 | .BR auto=mdp5 . | |
172 | The default is 4. | |
7ef02d01 NB |
173 | |
174 | .TP | |
175 | .B bitmap= | |
176 | The option specifies a file in which a write-intent bitmap should be | |
177 | found. When assembling the array, | |
178 | .I mdadm | |
179 | will provide this file to the | |
180 | .B md | |
181 | driver as the bitmap file. This has the same function as the | |
7e23fc43 | 182 | .B \-\-bitmap\-file |
7ef02d01 | 183 | option to |
7e23fc43 | 184 | .BR \-\-assemble . |
058574b1 NB |
185 | |
186 | .TP | |
187 | .B metadata= | |
188 | Specify the metadata format that the array has. This is mainly | |
189 | recognised for comparability with the output of | |
7e23fc43 | 190 | .BR "mdadm \-Es" . |
058574b1 | 191 | |
11a3e71d | 192 | .RE |
e0d19036 NB |
193 | |
194 | .TP | |
195 | .B MAILADDR | |
196 | The | |
197 | .B mailaddr | |
198 | line gives an E-mail address that alerts should be | |
199 | sent to when | |
200 | .M mdadm | |
201 | is running in | |
7e23fc43 | 202 | .B \-\-monitor |
e0d19036 | 203 | mode (and was given the |
7e23fc43 | 204 | .B \-\-scan |
e0d19036 NB |
205 | option). There should only be one |
206 | .B MAILADDR | |
207 | line and it should have only one address. | |
208 | ||
209 | ||
4948b8f7 NB |
210 | .TP |
211 | .B MAILFROM | |
212 | The | |
213 | .B mailfrom | |
93e790af | 214 | line (which can only be abbreviated to at least 5 characters) gives an |
4948b8f7 NB |
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. | |
219 | ||
220 | Note that this value cannot be set via the | |
221 | .I mdadm | |
222 | commandline. It is only settable via the config file. | |
223 | ||
e0d19036 NB |
224 | .TP |
225 | .B PROGRAM | |
226 | The | |
227 | .B program | |
228 | line gives the name of a program to be run when | |
7e23fc43 | 229 | .B "mdadm \-\-monitor" |
e0d19036 NB |
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 | |
233 | device. | |
234 | ||
235 | There should only be one | |
236 | .B program | |
237 | line and it should be give only one program. | |
238 | ||
5bbb4842 NB |
239 | |
240 | .TP | |
241 | .B CREATE | |
242 | The | |
243 | .B create | |
058574b1 | 244 | line gives default values to be used when creating arrays and device entries for |
5bbb4842 NB |
245 | arrays. |
246 | These include: | |
247 | ||
248 | .RS 4 | |
249 | .TP | |
250 | .B owner= | |
251 | .TP | |
252 | .B group= | |
253 | These can give user/group ids or names to use instead of system | |
254 | defaults (root/wheel or root/disk). | |
255 | .TP | |
256 | .B mode= | |
257 | An octal file mode such as 0660 can be given to override the default | |
258 | of 0600. | |
259 | .TP | |
260 | .B auto= | |
261 | This corresponds to the | |
7e23fc43 | 262 | .B \-\-auto |
5bbb4842 NB |
263 | flag to mdadm. Give |
264 | .BR yes , | |
265 | .BR md , | |
266 | .BR mdp , | |
267 | .B part | |
b3f1c093 | 268 | \(em possibly followed by a number of partitions \(em to indicate how |
5bbb4842 NB |
269 | missing device entries should be created. |
270 | ||
058574b1 NB |
271 | .TP |
272 | .B metadata= | |
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. | |
275 | ||
38098016 NB |
276 | .TP |
277 | .B symlinks=no | |
278 | Normally when creating devices in | |
279 | .B /dev/md/ | |
280 | .I mdadm | |
281 | will create a matching symlink from | |
282 | .B /dev/ | |
283 | with a name starting | |
284 | .B md | |
285 | or | |
286 | .BR md_ . | |
287 | Give | |
16c4849b | 288 | .B symlinks=no |
38098016 | 289 | to suppress this symlink creation. |
5bbb4842 NB |
290 | .RE |
291 | ||
292 | ||
2d465520 NB |
293 | .SH EXAMPLE |
294 | DEVICE /dev/sd[bcdjkl]1 | |
295 | .br | |
296 | DEVICE /dev/hda1 /dev/hdb1 | |
297 | ||
93e790af | 298 | # /dev/md0 is known by its UID. |
2d465520 NB |
299 | .br |
300 | ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371 | |
301 | .br | |
302 | # /dev/md1 contains all devices with a minor number of | |
303 | .br | |
304 | # 1 in the superblock. | |
305 | .br | |
306 | ARRAY /dev/md1 superminor=1 | |
307 | .br | |
93e790af | 308 | # /dev/md2 is made from precisely these two devices |
2d465520 | 309 | .br |
a9d69660 | 310 | ARRAY /dev/md2 devices=/dev/hda1,/dev/hdb1 |
2d465520 NB |
311 | |
312 | # /dev/md4 and /dev/md5 are a spare-group and spares | |
313 | .br | |
314 | # can be moved between them | |
315 | .br | |
316 | ARRAY /dev/md4 uuid=b23f3c6d:aec43a9f:fd65db85:369432df | |
317 | .br | |
7e23fc43 | 318 | spare\-group=group1 |
2d465520 NB |
319 | .br |
320 | ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977 | |
321 | .br | |
7e23fc43 | 322 | spare\-group=group1 |
dd0781e5 NB |
323 | .br |
324 | # /dev/md/home is created if need to be a partitionable md array | |
325 | .br | |
326 | # any spare device number is allocated. | |
327 | .br | |
328 | ARRAY /dev/md/home UUID=9187a482:5dde19d9:eea3cc4a:d646ab8b | |
329 | .br | |
330 | auto=part | |
2d465520 NB |
331 | |
332 | MAILADDR root@mydomain.tld | |
333 | .br | |
7e23fc43 | 334 | PROGRAM /usr/sbin/handle\-mdadm\-events |
5bbb4842 | 335 | .br |
7e23fc43 | 336 | CREATE group=system mode=0640 auto=part\-8 |
41a3b72a NB |
337 | .br |
338 | HOMEHOST <system> | |
e0d19036 | 339 | |
56eb10c0 | 340 | .SH SEE ALSO |
11a3e71d NB |
341 | .BR mdadm (8), |
342 | .BR md (4). | |
56eb10c0 | 343 |