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52826846 | 1 | .\" -*- nroff -*- |
90fc992e NB |
2 | ''' Copyright Neil Brown and others. |
3 | ''' This program is free software; you can redistribute it and/or modify | |
4 | ''' it under the terms of the GNU General Public License as published by | |
5 | ''' the Free Software Foundation; either version 2 of the License, or | |
6 | ''' (at your option) any later version. | |
7 | ''' See file COPYING in distribution for details. | |
e003092c | 8 | .TH MDADM 8 "" v2.6.1 |
52826846 | 9 | .SH NAME |
9a9dab36 | 10 | mdadm \- manage MD devices |
cd29a5c8 NB |
11 | .I aka |
12 | Linux Software Raid. | |
13 | ||
52826846 NB |
14 | .SH SYNOPSIS |
15 | ||
e0d19036 | 16 | .BI mdadm " [mode] <raiddevice> [options] <component-devices>" |
52826846 | 17 | |
2ae555c3 | 18 | .SH DESCRIPTION |
52826846 | 19 | RAID devices are virtual devices created from two or more |
cd29a5c8 | 20 | real block devices. This allows multiple devices (typically disk |
35cc5be4 | 21 | drives or partitions thereof) to be combined into a single device to |
cd29a5c8 | 22 | hold (for example) a single filesystem. |
2d465520 | 23 | Some RAID levels include redundancy and so can survive some degree of |
cd29a5c8 NB |
24 | device failure. |
25 | ||
2d465520 NB |
26 | Linux Software RAID devices are implemented through the md (Multiple |
27 | Devices) device driver. | |
cd29a5c8 NB |
28 | |
29 | Currently, Linux supports | |
30 | .B LINEAR | |
31 | md devices, | |
32 | .B RAID0 | |
33 | (striping), | |
34 | .B RAID1 | |
35 | (mirroring), | |
d013a55e NB |
36 | .BR RAID4 , |
37 | .BR RAID5 , | |
98c6faba | 38 | .BR RAID6 , |
1a7dfc35 | 39 | .BR RAID10 , |
b5e64645 | 40 | .BR MULTIPATH , |
cd29a5c8 | 41 | and |
b5e64645 | 42 | .BR FAULTY . |
d013a55e | 43 | |
a9d69660 NB |
44 | .B MULTIPATH |
45 | is not a Software RAID mechanism, but does involve | |
d013a55e NB |
46 | multiple devices. For |
47 | .B MULTIPATH | |
48 | each device is a path to one common physical storage device. | |
49 | ||
a9d69660 NB |
50 | .B FAULTY |
51 | is also not true RAID, and it only involves one device. It | |
b5e64645 | 52 | provides a layer over a true device that can be used to inject faults. |
52826846 | 53 | |
a9d69660 NB |
54 | '''.B mdadm |
55 | '''is a program that can be used to create, manage, and monitor | |
56 | '''MD devices. As | |
57 | '''such it provides a similar set of functionality to the | |
58 | '''.B raidtools | |
59 | '''packages. | |
60 | '''The key differences between | |
61 | '''.B mdadm | |
62 | '''and | |
63 | '''.B raidtools | |
64 | '''are: | |
65 | '''.IP \(bu 4 | |
66 | '''.B mdadm | |
67 | '''is a single program and not a collection of programs. | |
68 | '''.IP \(bu 4 | |
69 | '''.B mdadm | |
70 | '''can perform (almost) all of its functions without having a | |
71 | '''configuration file and does not use one by default. Also | |
72 | '''.B mdadm | |
73 | '''helps with management of the configuration | |
74 | '''file. | |
75 | '''.IP \(bu 4 | |
76 | '''.B mdadm | |
77 | '''can provide information about your arrays (through Query, Detail, and Examine) | |
78 | '''that | |
79 | '''.B raidtools | |
80 | '''cannot. | |
81 | '''.P | |
82 | '''.I mdadm | |
83 | '''does not use | |
84 | '''.IR /etc/raidtab , | |
85 | '''the | |
86 | '''.B raidtools | |
87 | '''configuration file, at all. It has a different configuration file | |
98b24a2a | 88 | '''with a different format and a different purpose. |
52826846 NB |
89 | |
90 | .SH MODES | |
8382f19b | 91 | mdadm has several major modes of operation: |
cd29a5c8 NB |
92 | .TP |
93 | .B Assemble | |
94 | Assemble the parts of a previously created | |
52826846 | 95 | array into an active array. Components can be explicitly given |
2ae555c3 | 96 | or can be searched for. |
9a9dab36 | 97 | .B mdadm |
cd29a5c8 NB |
98 | checks that the components |
99 | do form a bona fide array, and can, on request, fiddle superblock | |
100 | information so as to assemble a faulty array. | |
101 | ||
102 | .TP | |
103 | .B Build | |
a9d69660 NB |
104 | Build an array that doesn't have per-device superblocks. For these |
105 | sorts of arrays, | |
106 | .I mdadm | |
107 | cannot differentiate between initial creation and subsequent assembly | |
108 | of an array. It also cannot perform any checks that appropriate | |
109 | devices have been requested. Because of this, the | |
110 | .B Build | |
111 | mode should only be used together with a complete understanding of | |
112 | what you are doing. | |
cd29a5c8 NB |
113 | |
114 | .TP | |
115 | .B Create | |
116 | Create a new array with per-device superblocks. | |
117 | '''It can progress | |
118 | '''in several step create-add-add-run or it can all happen with one command. | |
119 | ||
cd29a5c8 NB |
120 | .TP |
121 | .B "Follow or Monitor" | |
5787fa49 | 122 | Monitor one or more md devices and act on any state changes. This is |
1a7dfc35 | 123 | only meaningful for raid1, 4, 5, 6, 10 or multipath arrays as |
98c6faba NB |
124 | only these have interesting state. raid0 or linear never have |
125 | missing, spare, or failed drives, so there is nothing to monitor. | |
5787fa49 | 126 | |
dd0781e5 NB |
127 | .TP |
128 | .B "Grow" | |
129 | Grow (or shrink) an array, or otherwise reshape it in some way. | |
130 | Currently supported growth options including changing the active size | |
2ae555c3 | 131 | of component devices in RAID level 1/4/5/6 and changing the number of |
00be0b12 | 132 | active devices in RAID1/5/6. |
cd29a5c8 | 133 | |
8382f19b NB |
134 | .TP |
135 | .B "Incremental Assembly" | |
136 | Add a single device to an appropriate array. If the addition of the | |
137 | device makes the array runnable, the array will be started. | |
138 | This provides a convenient interface to a | |
139 | .I hot-plug | |
140 | system. As each device is detected, | |
141 | .I mdadm | |
142 | has a chance to include it in some array as appropriate. | |
143 | ||
2ae555c3 NB |
144 | .TP |
145 | .B Manage | |
146 | This is for doing things to specific components of an array such as | |
147 | adding new spares and removing faulty devices. | |
148 | ||
149 | .TP | |
150 | .B Misc | |
151 | This is an 'everything else' mode that supports operations on active | |
152 | arrays, operations on component devices such as erasing old superblocks, and | |
153 | information gathering operations. | |
154 | '''This mode allows operations on independent devices such as examine MD | |
155 | '''superblocks, erasing old superblocks and stopping active arrays. | |
156 | ||
1f48664b NB |
157 | .TP |
158 | .B Auto-detect | |
159 | This mode does not act on a specific device or array, but rather it | |
160 | requests the Linux Kernel to activate any auto-detected arrays. | |
52826846 NB |
161 | .SH OPTIONS |
162 | ||
2ae555c3 | 163 | .SH Options for selecting a mode are: |
52826846 | 164 | |
cd29a5c8 | 165 | .TP |
7e23fc43 | 166 | .BR \-A ", " \-\-assemble |
2d465520 | 167 | Assemble a pre-existing array. |
52826846 | 168 | |
cd29a5c8 | 169 | .TP |
7e23fc43 | 170 | .BR \-B ", " \-\-build |
cd29a5c8 | 171 | Build a legacy array without superblocks. |
52826846 | 172 | |
cd29a5c8 | 173 | .TP |
7e23fc43 | 174 | .BR \-C ", " \-\-create |
cd29a5c8 | 175 | Create a new array. |
52826846 | 176 | |
cd29a5c8 | 177 | .TP |
7e23fc43 | 178 | .BR \-F ", " \-\-follow ", " \-\-monitor |
cd29a5c8 NB |
179 | Select |
180 | .B Monitor | |
181 | mode. | |
52826846 | 182 | |
dd0781e5 | 183 | .TP |
7e23fc43 | 184 | .BR \-G ", " \-\-grow |
dd0781e5 | 185 | Change the size or shape of an active array. |
8382f19b NB |
186 | |
187 | .TP | |
1f48664b | 188 | .BR \-I ", " \-\-incremental |
8382f19b NB |
189 | Add a single device into an appropriate array, and possibly start the array. |
190 | ||
1f48664b NB |
191 | .TP |
192 | .B \-\-auto-detect | |
193 | Request that the kernel starts any auto-detected arrays. This can only | |
194 | work if | |
195 | .I md | |
196 | is compiled into the kernel \(em not if it is a module. | |
197 | Arrays can be auto-detected by the kernel if all the components are in | |
198 | primary MS-DOS partitions with partition type | |
199 | .BR FD . | |
200 | In-kernel autodetect is not recommended for new installations. Using | |
201 | .I mdadm | |
202 | to detect and assemble arrays \(em possibly in an | |
203 | .I initrd | |
204 | \(em is substantially more flexible and should be preferred. | |
205 | ||
2ae555c3 NB |
206 | .P |
207 | If a device is given before any options, or if the first option is | |
7e23fc43 PS |
208 | .BR \-\-add , |
209 | .BR \-\-fail , | |
2ae555c3 | 210 | or |
7e23fc43 | 211 | .BR \-\-remove , |
2ae555c3 NB |
212 | then the MANAGE mode is assume. |
213 | Anything other than these will cause the | |
214 | .B Misc | |
215 | mode to be assumed. | |
dd0781e5 | 216 | |
2ae555c3 | 217 | .SH Options that are not mode-specific are: |
e793c2e5 | 218 | |
cd29a5c8 | 219 | .TP |
7e23fc43 | 220 | .BR \-h ", " \-\-help |
a9d69660 NB |
221 | Display general help message or, after one of the above options, a |
222 | mode specific help message. | |
56eedc1a NB |
223 | |
224 | .TP | |
7e23fc43 | 225 | .B \-\-help\-options |
56eedc1a NB |
226 | Display more detailed help about command line parsing and some commonly |
227 | used options. | |
52826846 | 228 | |
cd29a5c8 | 229 | .TP |
7e23fc43 | 230 | .BR \-V ", " \-\-version |
9a9dab36 | 231 | Print version information for mdadm. |
52826846 | 232 | |
cd29a5c8 | 233 | .TP |
7e23fc43 | 234 | .BR \-v ", " \-\-verbose |
22892d56 NB |
235 | Be more verbose about what is happening. This can be used twice to be |
236 | extra-verbose. | |
a9d69660 | 237 | The extra verbosity currently only affects |
7e23fc43 | 238 | .B \-\-detail \-\-scan |
22892d56 | 239 | and |
7e23fc43 | 240 | .BR "\-\-examine \-\-scan" . |
52826846 | 241 | |
dab6685f | 242 | .TP |
7e23fc43 | 243 | .BR \-q ", " \-\-quiet |
dab6685f NB |
244 | Avoid printing purely informative messages. With this, |
245 | .B mdadm | |
246 | will be silent unless there is something really important to report. | |
247 | ||
cd29a5c8 | 248 | .TP |
7e23fc43 | 249 | .BR \-b ", " \-\-brief |
cd29a5c8 | 250 | Be less verbose. This is used with |
7e23fc43 | 251 | .B \-\-detail |
cd29a5c8 | 252 | and |
7e23fc43 | 253 | .BR \-\-examine . |
22892d56 | 254 | Using |
7e23fc43 | 255 | .B \-\-brief |
22892d56 | 256 | with |
7e23fc43 | 257 | .B \-\-verbose |
22892d56 | 258 | gives an intermediate level of verbosity. |
52826846 | 259 | |
e0d19036 | 260 | .TP |
7e23fc43 | 261 | .BR \-f ", " \-\-force |
e0d19036 NB |
262 | Be more forceful about certain operations. See the various modes of |
263 | the exact meaning of this option in different contexts. | |
264 | ||
265 | .TP | |
7e23fc43 | 266 | .BR \-c ", " \-\-config= |
2ae555c3 NB |
267 | Specify the config file. Default is to use |
268 | .BR /etc/mdadm.conf , | |
269 | or if that is missing, then | |
270 | .BR /etc/mdadm/mdadm.conf . | |
5787fa49 NB |
271 | If the config file given is |
272 | .B partitions | |
273 | then nothing will be read, but | |
274 | .I mdadm | |
275 | will act as though the config file contained exactly | |
276 | .B "DEVICE partitions" | |
277 | and will read | |
278 | .B /proc/partitions | |
279 | to find a list of devices to scan. | |
d013a55e NB |
280 | If the word |
281 | .B none | |
282 | is given for the config file, then | |
283 | .I mdadm | |
284 | will act as though the config file were empty. | |
e0d19036 NB |
285 | |
286 | .TP | |
7e23fc43 | 287 | .BR \-s ", " \-\-scan |
e0d19036 NB |
288 | scan config file or |
289 | .B /proc/mdstat | |
290 | for missing information. | |
291 | In general, this option gives | |
292 | .B mdadm | |
293 | permission to get any missing information, like component devices, | |
294 | array devices, array identities, and alert destination from the | |
295 | configuration file: | |
296 | .BR /etc/mdadm.conf . | |
297 | One exception is MISC mode when using | |
7e23fc43 | 298 | .B \-\-detail |
e0d19036 | 299 | or |
7e23fc43 | 300 | .B \-\-stop |
e0d19036 | 301 | in which case |
7e23fc43 | 302 | .B \-\-scan |
e0d19036 NB |
303 | says to get a list of array devices from |
304 | .BR /proc/mdstat . | |
305 | ||
570c0542 | 306 | .TP |
7e23fc43 | 307 | .B \-e ", " \-\-metadata= |
570c0542 | 308 | Declare the style of superblock (raid metadata) to be used. The |
53e8b987 | 309 | default is 0.90 for |
7e23fc43 | 310 | .BR \-\-create , |
53e8b987 | 311 | and to guess for other operations. |
2790ffe3 GB |
312 | The default can be overridden by setting the |
313 | .B metadata | |
314 | value for the | |
315 | .B CREATE | |
316 | keyword in | |
317 | .BR mdadm.conf . | |
570c0542 NB |
318 | |
319 | Options are: | |
320 | .RS | |
321 | .IP "0, 0.90, default" | |
322 | Use the original 0.90 format superblock. This format limits arrays to | |
323 | 28 componenet devices and limits component devices of levels 1 and | |
324 | greater to 2 terabytes. | |
325 | .IP "1, 1.0, 1.1, 1.2" | |
326 | Use the new version-1 format superblock. This has few restrictions. | |
327 | The different subversion store the superblock at different locations | |
328 | on the device, either at the end (for 1.0), at the start (for 1.1) or | |
329 | 4K from the start (for 1.2). | |
330 | .RE | |
331 | ||
41a3b72a | 332 | .TP |
7e23fc43 | 333 | .B \-\-homehost= |
35cc5be4 | 334 | This will override any |
41a3b72a NB |
335 | .B HOMEHOST |
336 | setting in the config file and provides the identify of the host which | |
337 | should be considered the home for any arrays. | |
338 | ||
339 | When creating an array, the | |
340 | .B homehost | |
341 | will be recorded in the superblock. For version-1 superblocks, it will | |
342 | be prefixed to the array name. For version-0.90 superblocks part of | |
343 | the SHA1 hash of the hostname will be stored in the later half of the | |
344 | UUID. | |
345 | ||
346 | When reporting information about an array, any array which is tagged | |
347 | for the given homehost will be reported as such. | |
348 | ||
349 | When using Auto-Assemble, only arrays tagged for the given homehost | |
350 | will be assembled. | |
351 | ||
2ae555c3 NB |
352 | .SH For create, build, or grow: |
353 | ||
354 | .TP | |
7e23fc43 | 355 | .BR \-n ", " \-\-raid\-devices= |
2ae555c3 NB |
356 | Specify the number of active devices in the array. This, plus the |
357 | number of spare devices (see below) must equal the number of | |
358 | .I component-devices | |
359 | (including "\fBmissing\fP" devices) | |
360 | that are listed on the command line for | |
7e23fc43 | 361 | .BR \-\-create . |
2ae555c3 NB |
362 | Setting a value of 1 is probably |
363 | a mistake and so requires that | |
7e23fc43 | 364 | .B \-\-force |
2ae555c3 NB |
365 | be specified first. A value of 1 will then be allowed for linear, |
366 | multipath, raid0 and raid1. It is never allowed for raid4 or raid5. | |
367 | .br | |
368 | This number can only be changed using | |
7e23fc43 | 369 | .B \-\-grow |
00be0b12 NB |
370 | for RAID1, RAID5 and RAID6 arrays, and only on kernels which provide |
371 | necessary support. | |
2ae555c3 NB |
372 | |
373 | .TP | |
7e23fc43 | 374 | .BR \-x ", " \-\-spare\-devices= |
2ae555c3 NB |
375 | Specify the number of spare (eXtra) devices in the initial array. |
376 | Spares can also be added | |
377 | and removed later. The number of component devices listed | |
378 | on the command line must equal the number of raid devices plus the | |
379 | number of spare devices. | |
380 | ||
381 | ||
382 | .TP | |
7e23fc43 | 383 | .BR \-z ", " \-\-size= |
2ae555c3 NB |
384 | Amount (in Kibibytes) of space to use from each drive in RAID1/4/5/6. |
385 | This must be a multiple of the chunk size, and must leave about 128Kb | |
386 | of space at the end of the drive for the RAID superblock. | |
387 | If this is not specified | |
388 | (as it normally is not) the smallest drive (or partition) sets the | |
389 | size, though if there is a variance among the drives of greater than 1%, a warning is | |
390 | issued. | |
391 | ||
392 | This value can be set with | |
7e23fc43 | 393 | .B \-\-grow |
2ae555c3 NB |
394 | for RAID level 1/4/5/6. If the array was created with a size smaller |
395 | than the currently active drives, the extra space can be accessed | |
396 | using | |
7e23fc43 | 397 | .BR \-\-grow . |
2ae555c3 NB |
398 | The size can be given as |
399 | .B max | |
400 | which means to choose the largest size that fits on all current drives. | |
52826846 | 401 | |
cd29a5c8 | 402 | .TP |
7e23fc43 | 403 | .BR \-c ", " \-\-chunk= |
cd29a5c8 | 404 | Specify chunk size of kibibytes. The default is 64. |
52826846 | 405 | |
cd29a5c8 | 406 | .TP |
7e23fc43 | 407 | .BR \-\-rounding= |
cd29a5c8 | 408 | Specify rounding factor for linear array (==chunk size) |
52826846 | 409 | |
cd29a5c8 | 410 | .TP |
7e23fc43 | 411 | .BR \-l ", " \-\-level= |
aa88f531 | 412 | Set raid level. When used with |
7e23fc43 | 413 | .BR \-\-create , |
98c6faba | 414 | options are: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4, |
2ae555c3 | 415 | raid5, 5, raid6, 6, raid10, 10, multipath, mp, faulty. Obviously some of these are synonymous. |
aa88f531 NB |
416 | |
417 | When used with | |
7e23fc43 | 418 | .BR \-\-build , |
a9d69660 | 419 | only linear, stripe, raid0, 0, raid1, multipath, mp, and faulty are valid. |
52826846 | 420 | |
2ae555c3 | 421 | Not yet supported with |
7e23fc43 | 422 | .BR \-\-grow . |
2ae555c3 | 423 | |
cd29a5c8 | 424 | .TP |
7e23fc43 | 425 | .BR \-p ", " \-\-layout= |
1a7dfc35 NB |
426 | This option configures the fine details of data layout for raid5, |
427 | and raid10 arrays, and controls the failure modes for | |
428 | .IR faulty . | |
429 | ||
430 | The layout of the raid5 parity block can be one of | |
7e23fc43 PS |
431 | .BR left\-asymmetric , |
432 | .BR left\-symmetric , | |
433 | .BR right\-asymmetric , | |
434 | .BR right\-symmetric , | |
53e8b987 PS |
435 | .BR la ", " ra ", " ls ", " rs . |
436 | The default is | |
7e23fc43 | 437 | .BR left\-symmetric . |
52826846 | 438 | |
1a7dfc35 NB |
439 | When setting the failure mode for |
440 | .I faulty | |
441 | the options are: | |
7e23fc43 PS |
442 | .BR write\-transient ", " wt , |
443 | .BR read\-transient ", " rt , | |
444 | .BR write\-persistent ", " wp , | |
445 | .BR read\-persistent ", " rp , | |
446 | .BR write\-all , | |
447 | .BR read\-fixable ", " rf , | |
53e8b987 | 448 | .BR clear ", " flush ", " none . |
b5e64645 NB |
449 | |
450 | Each mode can be followed by a number which is used as a period | |
451 | between fault generation. Without a number, the fault is generated | |
452 | once on the first relevant request. With a number, the fault will be | |
453 | generated after that many request, and will continue to be generated | |
454 | every time the period elapses. | |
455 | ||
456 | Multiple failure modes can be current simultaneously by using the | |
7e23fc43 | 457 | .B \-\-grow |
53e8b987 | 458 | option to set subsequent failure modes. |
b5e64645 NB |
459 | |
460 | "clear" or "none" will remove any pending or periodic failure modes, | |
2ae555c3 | 461 | and "flush" will clear any persistent faults. |
b5e64645 | 462 | |
53e8b987 | 463 | To set the parity with |
7e23fc43 | 464 | .BR \-\-grow , |
53e8b987 | 465 | the level of the array ("faulty") |
b5e64645 NB |
466 | must be specified before the fault mode is specified. |
467 | ||
6f9a21a7 | 468 | Finally, the layout options for RAID10 are one of 'n', 'o' or 'f' followed |
1a7dfc35 NB |
469 | by a small number. The default is 'n2'. |
470 | ||
471 | .I n | |
b578481c NB |
472 | signals 'near' copies. Multiple copies of one data block are at |
473 | similar offsets in different devices. | |
474 | ||
475 | .I o | |
476 | signals 'offset' copies. Rather than the chunks being duplicated | |
477 | within a stripe, whole stripes are duplicated but are rotated by one | |
478 | device so duplicate blocks are on different devices. Thus subsequent | |
479 | copies of a block are in the next drive, and are one chunk further | |
480 | down. | |
481 | ||
1a7dfc35 NB |
482 | .I f |
483 | signals 'far' copies | |
484 | (multiple copies have very different offsets). See md(4) for more | |
485 | detail about 'near' and 'far'. | |
486 | ||
487 | The number is the number of copies of each datablock. 2 is normal, 3 | |
488 | can be useful. This number can be at most equal to the number of | |
489 | devices in the array. It does not need to divide evenly into that | |
490 | number (e.g. it is perfectly legal to have an 'n2' layout for an array | |
491 | with an odd number of devices). | |
492 | ||
cd29a5c8 | 493 | .TP |
7e23fc43 | 494 | .BR \-\-parity= |
53e8b987 | 495 | same as |
7e23fc43 | 496 | .B \-\-layout |
53e8b987 | 497 | (thus explaining the p of |
7e23fc43 | 498 | .BR \-p ). |
52826846 | 499 | |
e793c2e5 | 500 | .TP |
7e23fc43 | 501 | .BR \-b ", " \-\-bitmap= |
e793c2e5 | 502 | Specify a file to store a write-intent bitmap in. The file should not |
53e8b987 | 503 | exist unless |
7e23fc43 | 504 | .B \-\-force |
53e8b987 | 505 | is also given. The same file should be provided |
2ae555c3 NB |
506 | when assembling the array. If the word |
507 | .B internal | |
508 | is given, then the bitmap is stored with the metadata on the array, | |
509 | and so is replicated on all devices. If the word | |
510 | .B none | |
511 | is given with | |
7e23fc43 | 512 | .B \-\-grow |
2ae555c3 | 513 | mode, then any bitmap that is present is removed. |
e793c2e5 | 514 | |
2ae555c3 NB |
515 | To help catch typing errors, the filename must contain at least one |
516 | slash ('/') if it is a real file (not 'internal' or 'none'). | |
517 | ||
518 | Note: external bitmaps are only known to work on ext2 and ext3. | |
519 | Storing bitmap files on other filesystems may result in serious problems. | |
e793c2e5 | 520 | |
cd29a5c8 | 521 | .TP |
7e23fc43 | 522 | .BR \-\-bitmap\-chunk= |
2ae555c3 | 523 | Set the chunksize of the bitmap. Each bit corresponds to that many |
1bfdbe01 NB |
524 | Kilobytes of storage. |
525 | When using a file based bitmap, the default is to use the smallest | |
526 | size that is atleast 4 and requires no more than 2^21 chunks. | |
2ae555c3 NB |
527 | When using an |
528 | .B internal | |
529 | bitmap, the chunksize is automatically determined to make best use of | |
530 | available space. | |
5787fa49 | 531 | |
cd29a5c8 NB |
532 | |
533 | .TP | |
7e23fc43 | 534 | .BR \-W ", " \-\-write\-mostly |
2ae555c3 | 535 | subsequent devices lists in a |
7e23fc43 PS |
536 | .BR \-\-build , |
537 | .BR \-\-create , | |
2ae555c3 | 538 | or |
7e23fc43 | 539 | .B \-\-add |
2ae555c3 NB |
540 | command will be flagged as 'write-mostly'. This is valid for RAID1 |
541 | only and means that the 'md' driver will avoid reading from these | |
542 | devices if at all possible. This can be useful if mirroring over a | |
543 | slow link. | |
52826846 | 544 | |
2ae555c3 | 545 | .TP |
7e23fc43 | 546 | .BR \-\-write\-behind= |
2ae555c3 NB |
547 | Specify that write-behind mode should be enabled (valid for RAID1 |
548 | only). If an argument is specified, it will set the maximum number | |
549 | of outstanding writes allowed. The default value is 256. | |
550 | A write-intent bitmap is required in order to use write-behind | |
551 | mode, and write-behind is only attempted on drives marked as | |
552 | .IR write-mostly . | |
dd0781e5 NB |
553 | |
554 | .TP | |
7e23fc43 | 555 | .BR \-\-assume\-clean |
dd0781e5 NB |
556 | Tell |
557 | .I mdadm | |
47d79ef8 NB |
558 | that the array pre-existed and is known to be clean. It can be useful |
559 | when trying to recover from a major failure as you can be sure that no | |
560 | data will be affected unless you actually write to the array. It can | |
561 | also be used when creating a RAID1 or RAID10 if you want to avoid the | |
b3f1c093 | 562 | initial resync, however this practice \(em while normally safe \(em is not |
47d79ef8 | 563 | recommended. Use this ony if you really know what you are doing. |
dd0781e5 | 564 | |
2ae555c3 | 565 | .TP |
7e23fc43 | 566 | .BR \-\-backup\-file= |
53e8b987 | 567 | This is needed when |
7e23fc43 | 568 | .B \-\-grow |
53e8b987 | 569 | is used to increase the number of |
2ae555c3 NB |
570 | raid-devices in a RAID5 if there are no spare devices available. |
571 | See the section below on RAID_DEVICE CHANGES. The file should be | |
572 | stored on a separate device, not on the raid array being reshaped. | |
573 | ||
947fd4dd | 574 | .TP |
7e23fc43 | 575 | .BR \-N ", " \-\-name= |
947fd4dd NB |
576 | Set a |
577 | .B name | |
578 | for the array. This is currently only effective when creating an | |
579 | array with a version-1 superblock. The name is a simple textual | |
580 | string that can be used to identify array components when assembling. | |
581 | ||
dd0781e5 | 582 | .TP |
7e23fc43 | 583 | .BR \-R ", " \-\-run |
dd0781e5 NB |
584 | Insist that |
585 | .I mdadm | |
586 | run the array, even if some of the components | |
587 | appear to be active in another array or filesystem. Normally | |
588 | .I mdadm | |
589 | will ask for confirmation before including such components in an | |
590 | array. This option causes that question to be suppressed. | |
591 | ||
592 | .TP | |
7e23fc43 | 593 | .BR \-f ", " \-\-force |
dd0781e5 NB |
594 | Insist that |
595 | .I mdadm | |
596 | accept the geometry and layout specified without question. Normally | |
597 | .I mdadm | |
598 | will not allow creation of an array with only one device, and will try | |
599 | to create a raid5 array with one missing drive (as this makes the | |
600 | initial resync work faster). With | |
7e23fc43 | 601 | .BR \-\-force , |
dd0781e5 NB |
602 | .I mdadm |
603 | will not try to be so clever. | |
604 | ||
605 | .TP | |
7e23fc43 | 606 | .BR \-a ", " "\-\-auto{=no,yes,md,mdp,part,p}{NN}" |
48f7b27a NB |
607 | Instruct mdadm to create the device file if needed, possibly allocating |
608 | an unused minor number. "md" causes a non-partitionable array | |
dd0781e5 | 609 | to be used. "mdp", "part" or "p" causes a partitionable array (2.6 and |
2ae555c3 | 610 | later) to be used. "yes" requires the named md device to have |
f9c25f1d | 611 | a 'standard' format, and the type and minor number will be determined |
48f7b27a NB |
612 | from this. See DEVICE NAMES below. |
613 | ||
a9d69660 | 614 | The argument can also come immediately after |
7e23fc43 | 615 | "\-a". e.g. "\-ap". |
dd0781e5 | 616 | |
53e8b987 | 617 | If |
7e23fc43 | 618 | .B \-\-auto |
53e8b987 | 619 | is not given on the command line or in the config file, then |
75723446 | 620 | the default will be |
7e23fc43 | 621 | .BR \-\-auto=yes . |
75723446 | 622 | |
1337546d | 623 | If |
7e23fc43 | 624 | .B \-\-scan |
1337546d NB |
625 | is also given, then any |
626 | .I auto= | |
35cc5be4 | 627 | entries in the config file will override the |
7e23fc43 | 628 | .B \-\-auto |
1337546d NB |
629 | instruction given on the command line. |
630 | ||
dd0781e5 NB |
631 | For partitionable arrays, |
632 | .I mdadm | |
633 | will create the device file for the whole array and for the first 4 | |
634 | partitions. A different number of partitions can be specified at the | |
635 | end of this option (e.g. | |
7e23fc43 | 636 | .BR \-\-auto=p7 ). |
2ae555c3 | 637 | If the device name ends with a digit, the partition names add a 'p', |
48f7b27a | 638 | and a number, e.g. "/dev/home1p3". If there is no |
dd0781e5 NB |
639 | trailing digit, then the partition names just have a number added, |
640 | e.g. "/dev/scratch3". | |
641 | ||
48f7b27a NB |
642 | If the md device name is in a 'standard' format as described in DEVICE |
643 | NAMES, then it will be created, if necessary, with the appropriate | |
644 | number based on that name. If the device name is not in one of these | |
a9d69660 | 645 | formats, then a unused minor number will be allocated. The minor |
48f7b27a NB |
646 | number will be considered unused if there is no active array for that |
647 | number, and there is no entry in /dev for that number and with a | |
648 | non-standard name. | |
649 | ||
38098016 | 650 | .TP |
7e23fc43 | 651 | .BR \-\-symlink = no |
38098016 | 652 | Normally when |
7e23fc43 | 653 | .B \-\-auto |
38098016 NB |
654 | causes |
655 | .I mdadm | |
656 | to create devices in | |
657 | .B /dev/md/ | |
658 | it will also create symlinks from | |
659 | .B /dev/ | |
660 | with names starting with | |
661 | .B md | |
662 | or | |
663 | .BR md_ . | |
664 | Use | |
7e23fc43 | 665 | .B \-\-symlink=no |
38098016 | 666 | to suppress this, or |
7e23fc43 | 667 | .B \-\-symlink=yes |
38098016 NB |
668 | to enforce this even if it is suppressing |
669 | .IR mdadm.conf . | |
670 | ||
671 | ||
52826846 NB |
672 | .SH For assemble: |
673 | ||
cd29a5c8 | 674 | .TP |
7e23fc43 | 675 | .BR \-u ", " \-\-uuid= |
cd29a5c8 NB |
676 | uuid of array to assemble. Devices which don't have this uuid are |
677 | excluded | |
678 | ||
679 | .TP | |
7e23fc43 | 680 | .BR \-m ", " \-\-super\-minor= |
cd29a5c8 NB |
681 | Minor number of device that array was created for. Devices which |
682 | don't have this minor number are excluded. If you create an array as | |
2d465520 | 683 | /dev/md1, then all superblocks will contain the minor number 1, even if |
cd29a5c8 NB |
684 | the array is later assembled as /dev/md2. |
685 | ||
d013a55e | 686 | Giving the literal word "dev" for |
7e23fc43 | 687 | .B \-\-super\-minor |
d013a55e NB |
688 | will cause |
689 | .I mdadm | |
690 | to use the minor number of the md device that is being assembled. | |
691 | e.g. when assembling | |
692 | .BR /dev/md0 , | |
7e23fc43 | 693 | .M \-\-super\-minor=dev |
d013a55e NB |
694 | will look for super blocks with a minor number of 0. |
695 | ||
947fd4dd | 696 | .TP |
7e23fc43 | 697 | .BR \-N ", " \-\-name= |
947fd4dd | 698 | Specify the name of the array to assemble. This must be the name |
624920bb NB |
699 | that was specified when creating the array. It must either match |
700 | then name stored in the superblock exactly, or it must match | |
41a3b72a | 701 | with the current |
624920bb NB |
702 | .I homehost |
703 | is added to the start of the given name. | |
947fd4dd | 704 | |
cd29a5c8 | 705 | .TP |
7e23fc43 | 706 | .BR \-f ", " \-\-force |
52826846 NB |
707 | Assemble the array even if some superblocks appear out-of-date |
708 | ||
cd29a5c8 | 709 | .TP |
7e23fc43 | 710 | .BR \-R ", " \-\-run |
b8a8ccf9 NB |
711 | Attempt to start the array even if fewer drives were given than were |
712 | present last time the array was active. Normally if not all the | |
713 | expected drives are found and | |
7e23fc43 | 714 | .B \-\-scan |
cd29a5c8 NB |
715 | is not used, then the array will be assembled but not started. |
716 | With | |
7e23fc43 | 717 | .B \-\-run |
cd29a5c8 | 718 | an attempt will be made to start it anyway. |
52826846 | 719 | |
b8a8ccf9 | 720 | .TP |
7e23fc43 | 721 | .B \-\-no\-degraded |
b8a8ccf9 | 722 | This is the reverse of |
7e23fc43 | 723 | .B \-\-run |
b8a8ccf9 NB |
724 | in that it inhibits the started if array unless all expected drives |
725 | are present. This is only needed with | |
7e23fc43 | 726 | .B \-\-scan |
b8a8ccf9 NB |
727 | and can be used if you physical connections to devices are |
728 | not as reliable as you would like. | |
729 | ||
dd0781e5 | 730 | .TP |
7e23fc43 | 731 | .BR \-a ", " "\-\-auto{=no,yes,md,mdp,part}" |
dd0781e5 NB |
732 | See this option under Create and Build options. |
733 | ||
e793c2e5 | 734 | .TP |
7e23fc43 | 735 | .BR \-b ", " \-\-bitmap= |
2ae555c3 NB |
736 | Specify the bitmap file that was given when the array was created. If |
737 | an array has an | |
738 | .B internal | |
739 | bitmap, there is no need to specify this when assembling the array. | |
740 | ||
741 | .TP | |
7e23fc43 | 742 | .BR \-\-backup\-file= |
2ae555c3 | 743 | If |
7e23fc43 | 744 | .B \-\-backup\-file |
2ae555c3 NB |
745 | was used to grow the number of raid-devices in a RAID5, and the system |
746 | crashed during the critical section, then the same | |
7e23fc43 | 747 | .B \-\-backup\-file |
53e8b987 | 748 | must be presented to |
7e23fc43 | 749 | .B \-\-assemble |
53e8b987 | 750 | to allow possibly corrupted data to be restored. |
e793c2e5 | 751 | |
5787fa49 | 752 | .TP |
7e23fc43 | 753 | .BR \-U ", " \-\-update= |
5787fa49 | 754 | Update the superblock on each device while assembling the array. The |
feb716e9 NB |
755 | argument given to this flag can be one of |
756 | .BR sparc2.2 , | |
757 | .BR summaries , | |
7d99579f | 758 | .BR uuid , |
c4f12c13 | 759 | .BR name , |
0237e0ca | 760 | .BR homehost , |
e5329c37 | 761 | .BR resync , |
586ed405 | 762 | .BR byteorder , |
bee8ec56 | 763 | .BR devicesize , |
5787fa49 | 764 | or |
7e23fc43 | 765 | .BR super\-minor . |
5787fa49 NB |
766 | |
767 | The | |
768 | .B sparc2.2 | |
7d99579f | 769 | option will adjust the superblock of an array what was created on a Sparc |
5787fa49 NB |
770 | machine running a patched 2.2 Linux kernel. This kernel got the |
771 | alignment of part of the superblock wrong. You can use the | |
7e23fc43 | 772 | .B "\-\-examine \-\-sparc2.2" |
5787fa49 NB |
773 | option to |
774 | .I mdadm | |
775 | to see what effect this would have. | |
776 | ||
777 | The | |
7e23fc43 | 778 | .B super\-minor |
5787fa49 | 779 | option will update the |
2ae555c3 | 780 | .B "preferred minor" |
5787fa49 | 781 | field on each superblock to match the minor number of the array being |
45c073c9 NB |
782 | assembled. |
783 | This can be useful if | |
7e23fc43 | 784 | .B \-\-examine |
45c073c9 | 785 | reports a different "Preferred Minor" to |
7e23fc43 | 786 | .BR \-\-detail . |
45c073c9 NB |
787 | In some cases this update will be performed automatically |
788 | by the kernel driver. In particular the update happens automatically | |
789 | at the first write to an array with redundancy (RAID level 1 or | |
790 | greater) on a 2.6 (or later) kernel. | |
5787fa49 | 791 | |
7d99579f NB |
792 | The |
793 | .B uuid | |
794 | option will change the uuid of the array. If a UUID is given with the | |
7e23fc43 | 795 | .B \-\-uuid |
53e8b987 | 796 | option that UUID will be used as a new UUID and will |
7d99579f NB |
797 | .B NOT |
798 | be used to help identify the devices in the array. | |
53e8b987 | 799 | If no |
7e23fc43 | 800 | .B \-\-uuid |
53e8b987 | 801 | is given, a random UUID is chosen. |
7d99579f | 802 | |
c4f12c13 NB |
803 | The |
804 | .B name | |
805 | option will change the | |
806 | .I name | |
807 | of the array as stored in the superblock. This is only supported for | |
808 | version-1 superblocks. | |
809 | ||
0237e0ca NB |
810 | The |
811 | .B homehost | |
812 | option will change the | |
813 | .I homehost | |
814 | as recorded in the superblock. For version-0 superblocks, this is the | |
815 | same as updating the UUID. | |
816 | For version-1 superblocks, this involves updating the name. | |
817 | ||
e5329c37 NB |
818 | The |
819 | .B resync | |
820 | option will cause the array to be marked | |
821 | .I dirty | |
822 | meaning that any redundancy in the array (e.g. parity for raid5, | |
823 | copies for raid1) may be incorrect. This will cause the raid system | |
824 | to perform a "resync" pass to make sure that all redundant information | |
825 | is correct. | |
826 | ||
586ed405 NB |
827 | The |
828 | .B byteorder | |
829 | option allows arrays to be moved between machines with different | |
830 | byte-order. | |
2ae555c3 | 831 | When assembling such an array for the first time after a move, giving |
7e23fc43 | 832 | .B "\-\-update=byteorder" |
586ed405 NB |
833 | will cause |
834 | .I mdadm | |
835 | to expect superblocks to have their byteorder reversed, and will | |
836 | correct that order before assembling the array. This is only valid | |
2ae555c3 | 837 | with original (Version 0.90) superblocks. |
586ed405 | 838 | |
feb716e9 NB |
839 | The |
840 | .B summaries | |
841 | option will correct the summaries in the superblock. That is the | |
842 | counts of total, working, active, failed, and spare devices. | |
5787fa49 | 843 | |
bee8ec56 NB |
844 | The |
845 | .B devicesize | |
846 | will rarely be of use. It applies to version 1.1 and 1.2 metadata | |
847 | only (where the metadata is at the start of the device) and is only | |
848 | useful when the component device has changed size (typically become | |
849 | larger). The version 1 metadata records the amount of the device that | |
850 | can be used to store data, so if a device in a version 1.1 or 1.2 | |
851 | array becomes larger, the metadata will still be visible, but the | |
852 | extra space will not. In this case it might be useful to assemble the | |
853 | array with | |
7e23fc43 | 854 | .BR \-\-update=devicesize . |
bee8ec56 NB |
855 | This will cause |
856 | .I mdadm | |
857 | to determine the maximum usable amount of space on each device and | |
858 | update the relevant field in the metadata. | |
859 | ||
41a3b72a | 860 | .TP |
7e23fc43 | 861 | .B \-\-auto\-update\-homehost |
41a3b72a NB |
862 | This flag is only meaning with auto-assembly (see discussion below). |
863 | In that situation, if no suitable arrays are found for this homehost, | |
864 | .I mdadm | |
865 | will recan for any arrays at all and will assemble them and update the | |
866 | homehost to match the current host. | |
867 | ||
e0d19036 | 868 | .SH For Manage mode: |
52826846 | 869 | |
cd29a5c8 | 870 | .TP |
7e23fc43 | 871 | .BR \-a ", " \-\-add |
2ae555c3 | 872 | hot-add listed devices. |
52826846 | 873 | |
fe80f49b | 874 | .TP |
7e23fc43 | 875 | .BR \-\-re\-add |
2ae555c3 | 876 | re-add a device that was recently removed from an array. |
fe80f49b | 877 | |
cd29a5c8 | 878 | .TP |
7e23fc43 | 879 | .BR \-r ", " \-\-remove |
2d465520 | 880 | remove listed devices. They must not be active. i.e. they should |
b80da661 NB |
881 | be failed or spare devices. As well as the name of a device file |
882 | (e.g. | |
883 | .BR /dev/sda1 ) | |
884 | the words | |
885 | .B failed | |
886 | and | |
887 | .B detached | |
888 | can be given to | |
889 | .BR \-\-remove . | |
890 | The first causes all failed device to be removed. The second causes | |
891 | any device which is no longer connected to the system (i.e and open | |
892 | returns | |
893 | .BR ENXIO ) | |
894 | to be removed. This will only succeed for devices that are spares or | |
895 | have already been marked as failed. | |
52826846 | 896 | |
cd29a5c8 | 897 | .TP |
7e23fc43 | 898 | .BR \-f ", " \-\-fail |
cd29a5c8 | 899 | mark listed devices as faulty. |
b80da661 NB |
900 | As well as the name of a device file, the word |
901 | .B detached | |
902 | can be given. This will cause any device that has been detached from | |
903 | the system to be marked as failed. It can then be removed. | |
52826846 | 904 | |
cd29a5c8 | 905 | .TP |
7e23fc43 | 906 | .BR \-\-set\-faulty |
53e8b987 | 907 | same as |
7e23fc43 | 908 | .BR \-\-fail . |
52826846 | 909 | |
2ae555c3 NB |
910 | .P |
911 | Each of these options require that the first device list is the array | |
912 | to be acted upon and the remainder are component devices to be added, | |
913 | removed, or marked as fault. Several different operations can be | |
914 | specified for different devices, e.g. | |
915 | .in +5 | |
7e23fc43 | 916 | mdadm /dev/md0 \-\-add /dev/sda1 \-\-fail /dev/sdb1 \-\-remove /dev/sdb1 |
2ae555c3 NB |
917 | .in -5 |
918 | Each operation applies to all devices listed until the next | |
919 | operations. | |
920 | ||
921 | If an array is using a write-intent bitmap, then devices which have | |
922 | been removed can be re-added in a way that avoids a full | |
923 | reconstruction but instead just updated the blocks that have changed | |
924 | since the device was removed. For arrays with persistent metadata | |
925 | (superblocks) this is done automatically. For arrays created with | |
7e23fc43 | 926 | .B \-\-build |
2ae555c3 | 927 | mdadm needs to be told that this device we removed recently with |
7e23fc43 | 928 | .BR \-\-re\-add . |
2ae555c3 NB |
929 | |
930 | Devices can only be removed from an array if they are not in active | |
931 | use. i.e. that must be spares or failed devices. To remove an active | |
932 | device, it must be marked as | |
933 | .B faulty | |
934 | first. | |
935 | ||
936 | .SH For Misc mode: | |
937 | ||
938 | .TP | |
7e23fc43 | 939 | .BR \-Q ", " \-\-query |
2ae555c3 NB |
940 | Examine a device to see |
941 | (1) if it is an md device and (2) if it is a component of an md | |
942 | array. | |
943 | Information about what is discovered is presented. | |
944 | ||
945 | .TP | |
7e23fc43 | 946 | .BR \-D ", " \-\-detail |
2ae555c3 | 947 | Print detail of one or more md devices. |
5787fa49 | 948 | |
54bad364 KS |
949 | .TP |
950 | .BR \-Y ", " \-\-export | |
951 | When used with | |
952 | .BR \-\-detail , | |
953 | output will be formatted as | |
954 | .B key=value | |
955 | pairs for easy import into the environment. | |
956 | ||
2ae555c3 | 957 | .TP |
7e23fc43 | 958 | .BR \-E ", " \-\-examine |
2ae555c3 | 959 | Print content of md superblock on device(s). |
5787fa49 | 960 | .TP |
7e23fc43 | 961 | .B \-\-sparc2.2 |
a9d69660 | 962 | If an array was created on a 2.2 Linux kernel patched with RAID |
5787fa49 NB |
963 | support, the superblock will have been created incorrectly, or at |
964 | least incompatibly with 2.4 and later kernels. Using the | |
7e23fc43 | 965 | .B \-\-sparc2.2 |
5787fa49 | 966 | flag with |
7e23fc43 | 967 | .B \-\-examine |
5787fa49 NB |
968 | will fix the superblock before displaying it. If this appears to do |
969 | the right thing, then the array can be successfully assembled using | |
7e23fc43 | 970 | .BR "\-\-assemble \-\-update=sparc2.2" . |
5787fa49 | 971 | |
2ae555c3 | 972 | .TP |
7e23fc43 | 973 | .BR \-X ", " \-\-examine\-bitmap |
2ae555c3 | 974 | Report information about a bitmap file. |
e0d19036 | 975 | |
cd29a5c8 | 976 | .TP |
7e23fc43 | 977 | .BR \-R ", " \-\-run |
cd29a5c8 | 978 | start a partially built array. |
52826846 | 979 | |
cd29a5c8 | 980 | .TP |
7e23fc43 | 981 | .BR \-S ", " \-\-stop |
cd29a5c8 | 982 | deactivate array, releasing all resources. |
52826846 | 983 | |
cd29a5c8 | 984 | .TP |
7e23fc43 | 985 | .BR \-o ", " \-\-readonly |
cd29a5c8 | 986 | mark array as readonly. |
52826846 | 987 | |
cd29a5c8 | 988 | .TP |
7e23fc43 | 989 | .BR \-w ", " \-\-readwrite |
cd29a5c8 | 990 | mark array as readwrite. |
52826846 | 991 | |
e0d19036 | 992 | .TP |
7e23fc43 | 993 | .B \-\-zero\-superblock |
e0d19036 | 994 | If the device contains a valid md superblock, the block is |
35cc5be4 | 995 | overwritten with zeros. With |
7e23fc43 | 996 | .B \-\-force |
35cc5be4 | 997 | the block where the superblock would be is overwritten even if it |
e0d19036 | 998 | doesn't appear to be valid. |
52826846 | 999 | |
feb716e9 | 1000 | .TP |
7e23fc43 | 1001 | .BR \-t ", " \-\-test |
feb716e9 | 1002 | When used with |
7e23fc43 | 1003 | .BR \-\-detail , |
feb716e9 NB |
1004 | the exit status of |
1005 | .I mdadm | |
1006 | is set to reflect the status of the device. | |
1007 | ||
b90c0e9a | 1008 | .TP |
7e23fc43 | 1009 | .BR \-W ", " \-\-wait |
b90c0e9a NB |
1010 | For each md device given, wait for any resync, recovery, or reshape |
1011 | activity to finish before returning. | |
1012 | .I mdadm | |
1013 | will return with success if it actually waited for every device | |
1014 | listed, otherwise it will return failure. | |
1015 | ||
8382f19b NB |
1016 | .SH For Incremental Assembly mode: |
1017 | .TP | |
7e23fc43 | 1018 | .BR \-\-rebuild\-map ", " \-r |
8382f19b NB |
1019 | Rebuild the map file |
1020 | .RB ( /var/run/mdadm/map ) | |
1021 | that | |
1022 | .I mdadm | |
1023 | uses to help track which arrays are currently being assembled. | |
1024 | ||
1025 | .TP | |
7e23fc43 | 1026 | .BR \-\-run ", " \-R |
8382f19b NB |
1027 | Run any array assembled as soon as a minimal number of devices are |
1028 | available, rather than waiting until all expected devices are present. | |
1029 | ||
1030 | .TP | |
7e23fc43 | 1031 | .BR \-\-scan ", " \-s |
8382f19b | 1032 | Only meaningful with |
7e23fc43 | 1033 | .B \-R |
8382f19b NB |
1034 | this will scan the |
1035 | .B map | |
1036 | file for arrays that are being incrementally assembled and will try to | |
1037 | start any that are not already started. If any such array is listed | |
1038 | in | |
1039 | .B mdadm.conf | |
1040 | as requiring an external bitmap, that bitmap will be attached first. | |
1041 | ||
e0d19036 NB |
1042 | .SH For Monitor mode: |
1043 | .TP | |
7e23fc43 | 1044 | .BR \-m ", " \-\-mail |
e0d19036 NB |
1045 | Give a mail address to send alerts to. |
1046 | ||
1047 | .TP | |
7e23fc43 | 1048 | .BR \-p ", " \-\-program ", " \-\-alert |
e0d19036 NB |
1049 | Give a program to be run whenever an event is detected. |
1050 | ||
773135f5 | 1051 | .TP |
7e23fc43 | 1052 | .BR \-y ", " \-\-syslog |
773135f5 NB |
1053 | Cause all events to be reported through 'syslog'. The messages have |
1054 | facility of 'daemon' and varying priorities. | |
1055 | ||
e0d19036 | 1056 | .TP |
7e23fc43 | 1057 | .BR \-d ", " \-\-delay |
e0d19036 NB |
1058 | Give a delay in seconds. |
1059 | .B mdadm | |
1060 | polls the md arrays and then waits this many seconds before polling | |
1061 | again. The default is 60 seconds. | |
1062 | ||
d013a55e | 1063 | .TP |
7e23fc43 | 1064 | .BR \-f ", " \-\-daemonise |
d013a55e NB |
1065 | Tell |
1066 | .B mdadm | |
1067 | to run as a background daemon if it decides to monitor anything. This | |
1068 | causes it to fork and run in the child, and to disconnect form the | |
1069 | terminal. The process id of the child is written to stdout. | |
1070 | This is useful with | |
7e23fc43 | 1071 | .B \-\-scan |
d013a55e NB |
1072 | which will only continue monitoring if a mail address or alert program |
1073 | is found in the config file. | |
1074 | ||
b5e64645 | 1075 | .TP |
7e23fc43 | 1076 | .BR \-i ", " \-\-pid\-file |
b5e64645 NB |
1077 | When |
1078 | .B mdadm | |
1079 | is running in daemon mode, write the pid of the daemon process to | |
1080 | the specified file, instead of printing it on standard output. | |
1081 | ||
aa88f531 | 1082 | .TP |
7e23fc43 | 1083 | .BR \-1 ", " \-\-oneshot |
aa88f531 NB |
1084 | Check arrays only once. This will generate |
1085 | .B NewArray | |
1086 | events and more significantly | |
1087 | .B DegradedArray | |
a9d69660 NB |
1088 | and |
1089 | .B SparesMissing | |
aa88f531 NB |
1090 | events. Running |
1091 | .in +5 | |
7e23fc43 | 1092 | .B " mdadm \-\-monitor \-\-scan \-1" |
aa88f531 NB |
1093 | .in -5 |
1094 | from a cron script will ensure regular notification of any degraded arrays. | |
1095 | ||
98c6faba | 1096 | .TP |
7e23fc43 | 1097 | .BR \-t ", " \-\-test |
98c6faba NB |
1098 | Generate a |
1099 | .B TestMessage | |
1100 | alert for every array found at startup. This alert gets mailed and | |
1101 | passed to the alert program. This can be used for testing that alert | |
a9d69660 | 1102 | message do get through successfully. |
98c6faba | 1103 | |
e0d19036 | 1104 | .SH ASSEMBLE MODE |
52826846 | 1105 | |
cd29a5c8 NB |
1106 | .HP 12 |
1107 | Usage: | |
7e23fc43 | 1108 | .B mdadm \-\-assemble |
5787fa49 NB |
1109 | .I md-device options-and-component-devices... |
1110 | .HP 12 | |
1111 | Usage: | |
7e23fc43 | 1112 | .B mdadm \-\-assemble \-\-scan |
5787fa49 | 1113 | .I md-devices-and-options... |
cd29a5c8 NB |
1114 | .HP 12 |
1115 | Usage: | |
7e23fc43 | 1116 | .B mdadm \-\-assemble \-\-scan |
cd29a5c8 | 1117 | .I options... |
52826846 | 1118 | |
cd29a5c8 | 1119 | .PP |
52826846 | 1120 | This usage assembles one or more raid arrays from pre-existing components. |
9a9dab36 | 1121 | For each array, mdadm needs to know the md device, the identity of the |
e0d19036 | 1122 | array, and a number of component-devices. These can be found in a number of ways. |
52826846 | 1123 | |
5787fa49 | 1124 | In the first usage example (without the |
7e23fc43 | 1125 | .BR \-\-scan ) |
5787fa49 NB |
1126 | the first device given is the md device. |
1127 | In the second usage example, all devices listed are treated as md | |
1128 | devices and assembly is attempted. | |
1129 | In the third (where no devices are listed) all md devices that are | |
1130 | listed in the configuration file are assembled. | |
52826846 | 1131 | |
d013a55e | 1132 | If precisely one device is listed, but |
7e23fc43 | 1133 | .B \-\-scan |
dd0781e5 | 1134 | is not given, then |
d013a55e NB |
1135 | .I mdadm |
1136 | acts as though | |
7e23fc43 | 1137 | .B \-\-scan |
d013a55e NB |
1138 | was given and identify information is extracted from the configuration file. |
1139 | ||
2ae555c3 | 1140 | The identity can be given with the |
7e23fc43 | 1141 | .B \-\-uuid |
cd29a5c8 | 1142 | option, with the |
7e23fc43 | 1143 | .B \-\-super\-minor |
5787fa49 | 1144 | option, can be found in the config file, or will be taken from the |
e0d19036 | 1145 | super block on the first component-device listed on the command line. |
52826846 | 1146 | |
2ae555c3 | 1147 | Devices can be given on the |
7e23fc43 | 1148 | .B \-\-assemble |
5787fa49 NB |
1149 | command line or in the config file. Only devices which have an md |
1150 | superblock which contains the right identity will be considered for | |
1151 | any array. | |
52826846 | 1152 | |
2ae555c3 | 1153 | The config file is only used if explicitly named with |
7e23fc43 | 1154 | .B \-\-config |
d013a55e | 1155 | or requested with (a possibly implicit) |
7e23fc43 | 1156 | .BR \-\-scan . |
52826846 | 1157 | In the later case, |
9a9dab36 | 1158 | .B /etc/mdadm.conf |
52826846 NB |
1159 | is used. |
1160 | ||
2ae555c3 | 1161 | If |
7e23fc43 | 1162 | .B \-\-scan |
cd29a5c8 NB |
1163 | is not given, then the config file will only be used to find the |
1164 | identity of md arrays. | |
52826846 | 1165 | |
2d465520 | 1166 | Normally the array will be started after it is assembled. However if |
7e23fc43 | 1167 | .B \-\-scan |
2d465520 | 1168 | is not given and insufficient drives were listed to start a complete |
cd29a5c8 NB |
1169 | (non-degraded) array, then the array is not started (to guard against |
1170 | usage errors). To insist that the array be started in this case (as | |
1a7dfc35 | 1171 | may work for RAID1, 4, 5, 6, or 10), give the |
7e23fc43 | 1172 | .B \-\-run |
cd29a5c8 | 1173 | flag. |
52826846 | 1174 | |
75723446 NB |
1175 | If the md device does not exist, then it will be created providing the |
1176 | intent is clear. i.e. the name must be in a standard form, or the | |
7e23fc43 | 1177 | .B \-\-auto |
75723446 NB |
1178 | option must be given to clarify how and whether the device should be |
1179 | created. | |
dd0781e5 NB |
1180 | |
1181 | This can be useful for handling partitioned devices (which don't have | |
b3f1c093 | 1182 | a stable device number \(em it can change after a reboot) and when using |
dd0781e5 NB |
1183 | "udev" to manage your |
1184 | .B /dev | |
1185 | tree (udev cannot handle md devices because of the unusual device | |
1186 | initialisation conventions). | |
1187 | ||
1188 | If the option to "auto" is "mdp" or "part" or (on the command line | |
1189 | only) "p", then mdadm will create a partitionable array, using the | |
2ae555c3 | 1190 | first free one that is not in use, and does not already have an entry |
dd0781e5 NB |
1191 | in /dev (apart from numeric /dev/md* entries). |
1192 | ||
1193 | If the option to "auto" is "yes" or "md" or (on the command line) | |
1194 | nothing, then mdadm will create a traditional, non-partitionable md | |
1195 | array. | |
1196 | ||
1197 | It is expected that the "auto" functionality will be used to create | |
1198 | device entries with meaningful names such as "/dev/md/home" or | |
1199 | "/dev/md/root", rather than names based on the numerical array number. | |
1200 | ||
1201 | When using this option to create a partitionable array, the device | |
1202 | files for the first 4 partitions are also created. If a different | |
1203 | number is required it can be simply appended to the auto option. | |
1204 | e.g. "auto=part8". Partition names are created by appending a digit | |
a9d69660 | 1205 | string to the device name, with an intervening "p" if the device name |
dd0781e5 NB |
1206 | ends with a digit. |
1207 | ||
1208 | The | |
7e23fc43 | 1209 | .B \-\-auto |
dd0781e5 NB |
1210 | option is also available in Build and Create modes. As those modes do |
1211 | not use a config file, the "auto=" config option does not apply to | |
1212 | these modes. | |
52826846 | 1213 | |
41a3b72a NB |
1214 | .SS Auto Assembly |
1215 | When | |
7e23fc43 | 1216 | .B \-\-assemble |
41a3b72a | 1217 | is used with |
7e23fc43 | 1218 | .B \-\-scan |
41a3b72a NB |
1219 | and no devices are listed, |
1220 | .I mdadm | |
1221 | will first attempt to assemble all the arrays listed in the config | |
1222 | file. | |
1223 | ||
1224 | If a | |
1225 | .B homehost | |
1226 | has been specified (either in the config file or on the command line), | |
1227 | .I mdadm | |
1228 | will look further for possible arrays and will try to assemble | |
1229 | anything that it finds which is tagged as belonging to the given | |
1230 | homehost. This is the only situation where | |
1231 | .I mdadm | |
1232 | will assemble arrays without being given specific device name or | |
1233 | identify information for the array. | |
1234 | ||
1235 | If | |
1236 | .I mdadm | |
1237 | finds a consistent set of devices that look like they should comprise | |
1238 | an array, and if the superblock is tagged as belonging to the given | |
1239 | home host, it will automatically choose a device name and try to | |
1240 | assemble the array. If the array uses version-0.90 metadata, then the | |
1241 | .B minor | |
1242 | number as recorded in the superblock is used to create a name in | |
1243 | .B /dev/md/ | |
1244 | so for example | |
1245 | .BR /dev/md/3 . | |
1246 | If the array uses version-1 metadata, then the | |
1247 | .B name | |
1248 | from the superblock is used to similarly create a name in | |
1249 | .BR /dev/md . | |
1250 | The name will have any 'host' prefix stripped first. | |
1251 | ||
1252 | If | |
1253 | .I mdadm | |
1254 | cannot find any array for the given host at all, and if | |
7e23fc43 | 1255 | .B \-\-auto\-update\-homehost |
41a3b72a NB |
1256 | is given, then |
1257 | .I mdadm | |
1258 | will search again for any array (not just an array created for this | |
1259 | host) and will assemble each assuming | |
7e23fc43 | 1260 | .BR \-\-update=homehost . |
41a3b72a NB |
1261 | This will change the host tag in the superblock so that on the next run, |
1262 | these arrays will be found without the second pass. The intention of | |
1263 | this feature is to support transitioning a set of md arrays to using | |
1264 | homehost tagging. | |
1265 | ||
1266 | The reason for requiring arrays to be tagged with the homehost for | |
1267 | auto assembly is to guard against problems that can arise when moving | |
1268 | devices from one host to another. | |
1269 | ||
cd29a5c8 | 1270 | .SH BUILD MODE |
52826846 | 1271 | |
cd29a5c8 NB |
1272 | .HP 12 |
1273 | Usage: | |
7e23fc43 | 1274 | .B mdadm \-\-build |
cd29a5c8 | 1275 | .I device |
7e23fc43 PS |
1276 | .BI \-\-chunk= X |
1277 | .BI \-\-level= Y | |
1278 | .BI \-\-raid\-devices= Z | |
cd29a5c8 NB |
1279 | .I devices |
1280 | ||
1281 | .PP | |
2ae555c3 | 1282 | This usage is similar to |
7e23fc43 | 1283 | .BR \-\-create . |
a9d69660 | 1284 | The difference is that it creates an array without a superblock. With |
cd29a5c8 | 1285 | these arrays there is no difference between initially creating the array and |
52826846 NB |
1286 | subsequently assembling the array, except that hopefully there is useful |
1287 | data there in the second case. | |
1288 | ||
a9d69660 NB |
1289 | The level may raid0, linear, multipath, or faulty, or one of their |
1290 | synonyms. All devices must be listed and the array will be started | |
1291 | once complete. | |
cd29a5c8 NB |
1292 | |
1293 | .SH CREATE MODE | |
1294 | ||
1295 | .HP 12 | |
1296 | Usage: | |
7e23fc43 | 1297 | .B mdadm \-\-create |
cd29a5c8 | 1298 | .I device |
7e23fc43 PS |
1299 | .BI \-\-chunk= X |
1300 | .BI \-\-level= Y | |
cd29a5c8 | 1301 | .br |
7e23fc43 | 1302 | .BI \-\-raid\-devices= Z |
cd29a5c8 NB |
1303 | .I devices |
1304 | ||
1305 | .PP | |
1306 | This usage will initialise a new md array, associate some devices with | |
1307 | it, and activate the array. | |
1308 | ||
a9d69660 | 1309 | If the |
7e23fc43 | 1310 | .B \-\-auto |
dd0781e5 NB |
1311 | option is given (as described in more detail in the section on |
1312 | Assemble mode), then the md device will be created with a suitable | |
1313 | device number if necessary. | |
1314 | ||
cd29a5c8 | 1315 | As devices are added, they are checked to see if they contain raid |
2d465520 | 1316 | superblocks or filesystems. They are also checked to see if the variance in |
cd29a5c8 NB |
1317 | device size exceeds 1%. |
1318 | ||
1319 | If any discrepancy is found, the array will not automatically be run, though | |
2ae555c3 | 1320 | the presence of a |
7e23fc43 | 1321 | .B \-\-run |
cd29a5c8 NB |
1322 | can override this caution. |
1323 | ||
2d465520 | 1324 | To create a "degraded" array in which some devices are missing, simply |
d013a55e | 1325 | give the word "\fBmissing\fP" |
2d465520 NB |
1326 | in place of a device name. This will cause |
1327 | .B mdadm | |
1328 | to leave the corresponding slot in the array empty. | |
1329 | For a RAID4 or RAID5 array at most one slot can be | |
98c6faba | 1330 | "\fBmissing\fP"; for a RAID6 array at most two slots. |
2d465520 NB |
1331 | For a RAID1 array, only one real device needs to be given. All of the |
1332 | others can be | |
d013a55e | 1333 | "\fBmissing\fP". |
2d465520 | 1334 | |
feb716e9 NB |
1335 | When creating a RAID5 array, |
1336 | .B mdadm | |
1337 | will automatically create a degraded array with an extra spare drive. | |
1338 | This is because building the spare into a degraded array is in general faster than resyncing | |
1339 | the parity on a non-degraded, but not clean, array. This feature can | |
35cc5be4 | 1340 | be overridden with the |
7e23fc43 | 1341 | .B \-\-force |
feb716e9 NB |
1342 | option. |
1343 | ||
41a3b72a NB |
1344 | When creating an array with version-1 metadata a name for the host is |
1345 | required. | |
1346 | If this is not given with the | |
7e23fc43 | 1347 | .B \-\-name |
41a3b72a NB |
1348 | option, |
1349 | .I mdadm | |
1350 | will chose a name based on the last component of the name of the | |
1351 | device being created. So if | |
1352 | .B /dev/md3 | |
1353 | is being created, then the name | |
1354 | .B 3 | |
1355 | will be chosen. | |
1356 | If | |
1357 | .B /dev/md/home | |
1358 | is being created, then the name | |
1359 | .B home | |
1360 | will be used. | |
1361 | ||
3d3dd91e NB |
1362 | A new array will normally get a randomly assigned 128bit UUID which is |
1363 | very likely to be unique. If you have a specific need, you can choose | |
1364 | a UUID for the array by giving the | |
7e23fc43 | 1365 | .B \-\-uuid= |
3d3dd91e NB |
1366 | option. Be warned that creating two arrays with the same UUID is a |
1367 | recipe for disaster. Also, using | |
7e23fc43 | 1368 | .B \-\-uuid= |
3d3dd91e | 1369 | when creating a v0.90 array will silently override any |
7e23fc43 | 1370 | .B \-\-homehost= |
3d3dd91e | 1371 | setting. |
2ae555c3 | 1372 | '''If the |
7e23fc43 | 1373 | '''.B \-\-size |
e0d19036 | 1374 | '''option is given, it is not necessary to list any component-devices in this command. |
cd29a5c8 | 1375 | '''They can be added later, before a |
7e23fc43 | 1376 | '''.B \-\-run. |
2ae555c3 | 1377 | '''If no |
7e23fc43 | 1378 | '''.B \-\-size |
cd29a5c8 NB |
1379 | '''is given, the apparent size of the smallest drive given is used. |
1380 | ||
53e8b987 | 1381 | The General Management options that are valid with |
7e23fc43 | 1382 | .B \-\-create |
53e8b987 | 1383 | are: |
cd29a5c8 | 1384 | .TP |
7e23fc43 | 1385 | .B \-\-run |
dd0781e5 | 1386 | insist on running the array even if some devices look like they might |
cd29a5c8 NB |
1387 | be in use. |
1388 | ||
1389 | .TP | |
7e23fc43 | 1390 | .B \-\-readonly |
b3f1c093 | 1391 | start the array readonly \(em not supported yet. |
52826846 | 1392 | |
2ae555c3 | 1393 | |
e0d19036 | 1394 | .SH MANAGE MODE |
cd29a5c8 NB |
1395 | .HP 12 |
1396 | Usage: | |
e0d19036 NB |
1397 | .B mdadm |
1398 | .I device | |
1399 | .I options... devices... | |
cd29a5c8 NB |
1400 | .PP |
1401 | ||
e0d19036 NB |
1402 | This usage will allow individual devices in an array to be failed, |
1403 | removed or added. It is possible to perform multiple operations with | |
1404 | on command. For example: | |
1405 | .br | |
7e23fc43 | 1406 | .B " mdadm /dev/md0 \-f /dev/hda1 \-r /dev/hda1 \-a /dev/hda1" |
e0d19036 NB |
1407 | .br |
1408 | will firstly mark | |
1409 | .B /dev/hda1 | |
1410 | as faulty in | |
1411 | .B /dev/md0 | |
1412 | and will then remove it from the array and finally add it back | |
2d465520 | 1413 | in as a spare. However only one md array can be affected by a single |
2ae555c3 | 1414 | command. |
e0d19036 NB |
1415 | |
1416 | .SH MISC MODE | |
1417 | .HP 12 | |
1418 | Usage: | |
9a9dab36 | 1419 | .B mdadm |
e0d19036 NB |
1420 | .I options ... |
1421 | .I devices ... | |
1422 | .PP | |
cd29a5c8 | 1423 | |
b5e64645 | 1424 | MISC mode includes a number of distinct operations that |
e0d19036 NB |
1425 | operate on distinct devices. The operations are: |
1426 | .TP | |
7e23fc43 | 1427 | \-\-query |
e0d19036 NB |
1428 | The device is examined to see if it is |
1429 | (1) an active md array, or | |
1430 | (2) a component of an md array. | |
1431 | The information discovered is reported. | |
1432 | ||
1433 | .TP | |
7e23fc43 | 1434 | \-\-detail |
2d465520 NB |
1435 | The device should be an active md device. |
1436 | .B mdadm | |
1437 | will display a detailed description of the array. | |
7e23fc43 | 1438 | .B \-\-brief |
2d465520 | 1439 | or |
7e23fc43 | 1440 | .B \-\-scan |
2d465520 | 1441 | will cause the output to be less detailed and the format to be |
e0d19036 | 1442 | suitable for inclusion in |
9a9dab36 | 1443 | .BR /etc/mdadm.conf . |
feb716e9 NB |
1444 | The exit status of |
1445 | .I mdadm | |
1446 | will normally be 0 unless | |
1447 | .I mdadm | |
1448 | failed to get useful information about the device(s). However if the | |
7e23fc43 | 1449 | .B \-\-test |
feb716e9 NB |
1450 | option is given, then the exit status will be: |
1451 | .RS | |
1452 | .TP | |
1453 | 0 | |
1454 | The array is functioning normally. | |
1455 | .TP | |
1456 | 1 | |
1457 | The array has at least one failed device. | |
1458 | .TP | |
1459 | 2 | |
1460 | The array has multiple failed devices and hence is unusable (raid4 or | |
1461 | raid5). | |
1462 | .TP | |
1463 | 4 | |
1464 | There was an error while trying to get information about the device. | |
1465 | .RE | |
cd29a5c8 | 1466 | |
e0d19036 | 1467 | .TP |
7e23fc43 | 1468 | \-\-examine |
2d465520 NB |
1469 | The device should be a component of an md array. |
1470 | .B mdadm | |
1471 | will read the md superblock of the device and display the contents. | |
e0d19036 | 1472 | If |
7e23fc43 | 1473 | .B \-\-brief |
e0d19036 | 1474 | is given, or |
7e23fc43 | 1475 | .B \-\-scan |
e0d19036 NB |
1476 | then multiple devices that are components of the one array |
1477 | are grouped together and reported in a single entry suitable | |
1478 | for inclusion in | |
1479 | .BR /etc/mdadm.conf . | |
1480 | ||
2d465520 | 1481 | Having |
7e23fc43 | 1482 | .B \-\-scan |
e0d19036 NB |
1483 | without listing any devices will cause all devices listed in the |
1484 | config file to be examined. | |
1485 | ||
1486 | .TP | |
7e23fc43 | 1487 | \-\-stop |
98c6faba NB |
1488 | The devices should be active md arrays which will be deactivated, as |
1489 | long as they are not currently in use. | |
e0d19036 NB |
1490 | |
1491 | .TP | |
7e23fc43 | 1492 | \-\-run |
e0d19036 NB |
1493 | This will fully activate a partially assembled md array. |
1494 | ||
1495 | .TP | |
7e23fc43 | 1496 | \-\-readonly |
e0d19036 NB |
1497 | This will mark an active array as read-only, providing that it is |
1498 | not currently being used. | |
1499 | ||
1500 | .TP | |
7e23fc43 | 1501 | \-\-readwrite |
e0d19036 NB |
1502 | This will change a |
1503 | .B readonly | |
1504 | array back to being read/write. | |
1505 | ||
2d465520 | 1506 | .TP |
7e23fc43 | 1507 | \-\-scan |
2d465520 | 1508 | For all operations except |
7e23fc43 PS |
1509 | .BR \-\-examine , |
1510 | .B \-\-scan | |
2d465520 NB |
1511 | will cause the operation to be applied to all arrays listed in |
1512 | .BR /proc/mdstat . | |
1513 | For | |
7e23fc43 PS |
1514 | .BR \-\-examine, |
1515 | .B \-\-scan | |
2d465520 NB |
1516 | causes all devices listed in the config file to be examined. |
1517 | ||
1518 | ||
e0d19036 NB |
1519 | .SH MONITOR MODE |
1520 | ||
cd29a5c8 NB |
1521 | .HP 12 |
1522 | Usage: | |
7e23fc43 | 1523 | .B mdadm \-\-monitor |
e0d19036 NB |
1524 | .I options... devices... |
1525 | ||
cd29a5c8 | 1526 | .PP |
e0d19036 NB |
1527 | This usage causes |
1528 | .B mdadm | |
1529 | to periodically poll a number of md arrays and to report on any events | |
1530 | noticed. | |
1531 | .B mdadm | |
1532 | will never exit once it decides that there are arrays to be checked, | |
1533 | so it should normally be run in the background. | |
1534 | ||
2d465520 NB |
1535 | As well as reporting events, |
1536 | .B mdadm | |
1537 | may move a spare drive from one array to another if they are in the | |
1538 | same | |
1539 | .B spare-group | |
a9d69660 | 1540 | and if the destination array has a failed drive but no spares. |
2d465520 | 1541 | |
e0d19036 NB |
1542 | If any devices are listed on the command line, |
1543 | .B mdadm | |
1544 | will only monitor those devices. Otherwise all arrays listed in the | |
1545 | configuration file will be monitored. Further, if | |
7e23fc43 | 1546 | .B \-\-scan |
e0d19036 NB |
1547 | is given, then any other md devices that appear in |
1548 | .B /proc/mdstat | |
1549 | will also be monitored. | |
1550 | ||
1551 | The result of monitoring the arrays is the generation of events. | |
bd526cee | 1552 | These events are passed to a separate program (if specified) and may |
2d465520 | 1553 | be mailed to a given E-mail address. |
e0d19036 | 1554 | |
bd526cee | 1555 | When passing event to program, the program is run once for each event |
2ae555c3 | 1556 | and is given 2 or 3 command-line arguments. The first is the |
bd526cee NB |
1557 | name of the event (see below). The second is the name of the |
1558 | md device which is affected, and the third is the name of a related | |
1559 | device if relevant, such as a component device that has failed. | |
cd29a5c8 NB |
1560 | |
1561 | If | |
7e23fc43 | 1562 | .B \-\-scan |
e0d19036 NB |
1563 | is given, then a program or an E-mail address must be specified on the |
1564 | command line or in the config file. If neither are available, then | |
1565 | .B mdadm | |
1566 | will not monitor anything. | |
1567 | Without | |
7e23fc43 | 1568 | .B \-\-scan |
e0d19036 | 1569 | .B mdadm |
2d465520 | 1570 | will continue monitoring as long as something was found to monitor. If |
e0d19036 NB |
1571 | no program or email is given, then each event is reported to |
1572 | .BR stdout . | |
cd29a5c8 | 1573 | |
e0d19036 NB |
1574 | The different events are: |
1575 | ||
1576 | .RS 4 | |
1577 | .TP | |
1578 | .B DeviceDisappeared | |
2d465520 | 1579 | An md array which previously was configured appears to no longer be |
773135f5 | 1580 | configured. (syslog priority: Critical) |
e0d19036 | 1581 | |
b8f72a62 NB |
1582 | If |
1583 | .I mdadm | |
1584 | was told to monitor an array which is RAID0 or Linear, then it will | |
1585 | report | |
1586 | .B DeviceDisappeared | |
1587 | with the extra information | |
1588 | .BR Wrong-Level . | |
1589 | This is because RAID0 and Linear do not support the device-failed, | |
1590 | hot-spare and resync operations which are monitored. | |
1591 | ||
e0d19036 NB |
1592 | .TP |
1593 | .B RebuildStarted | |
773135f5 | 1594 | An md array started reconstruction. (syslog priority: Warning) |
e0d19036 NB |
1595 | |
1596 | .TP | |
1597 | .BI Rebuild NN | |
1598 | Where | |
1599 | .I NN | |
1600 | is 20, 40, 60, or 80, this indicates that rebuild has passed that many | |
773135f5 | 1601 | percentage of the total. (syslog priority: Warning) |
e0d19036 | 1602 | |
98c6faba NB |
1603 | .TP |
1604 | .B RebuildFinished | |
1605 | An md array that was rebuilding, isn't any more, either because it | |
773135f5 | 1606 | finished normally or was aborted. (syslog priority: Warning) |
98c6faba | 1607 | |
e0d19036 NB |
1608 | .TP |
1609 | .B Fail | |
773135f5 NB |
1610 | An active component device of an array has been marked as |
1611 | faulty. (syslog priority: Critical) | |
e0d19036 NB |
1612 | |
1613 | .TP | |
1614 | .B FailSpare | |
1615 | A spare component device which was being rebuilt to replace a faulty | |
773135f5 | 1616 | device has failed. (syslog priority: Critial) |
e0d19036 NB |
1617 | |
1618 | .TP | |
1619 | .B SpareActive | |
1620 | A spare component device which was being rebuilt to replace a faulty | |
98b24a2a | 1621 | device has been successfully rebuilt and has been made active. |
773135f5 | 1622 | (syslog priority: Info) |
e0d19036 NB |
1623 | |
1624 | .TP | |
1625 | .B NewArray | |
1626 | A new md array has been detected in the | |
1627 | .B /proc/mdstat | |
773135f5 | 1628 | file. (syslog priority: Info) |
e0d19036 | 1629 | |
aa88f531 NB |
1630 | .TP |
1631 | .B DegradedArray | |
1632 | A newly noticed array appears to be degraded. This message is not | |
1633 | generated when | |
1634 | .I mdadm | |
1635 | notices a drive failure which causes degradation, but only when | |
1636 | .I mdadm | |
1637 | notices that an array is degraded when it first sees the array. | |
773135f5 | 1638 | (syslog priority: Critial) |
aa88f531 | 1639 | |
e0d19036 NB |
1640 | .TP |
1641 | .B MoveSpare | |
1642 | A spare drive has been moved from one array in a | |
1643 | .B spare-group | |
1644 | to another to allow a failed drive to be replaced. | |
773135f5 | 1645 | (syslog priority: Info) |
e0d19036 | 1646 | |
b8f72a62 NB |
1647 | .TP |
1648 | .B SparesMissing | |
1649 | If | |
1650 | .I mdadm | |
1651 | has been told, via the config file, that an array should have a certain | |
1652 | number of spare devices, and | |
1653 | .I mdadm | |
1654 | detects that it has fewer that this number when it first sees the | |
1655 | array, it will report a | |
1656 | .B SparesMissing | |
1657 | message. | |
d1732eeb | 1658 | (syslog priority: Warning) |
b8f72a62 | 1659 | |
98c6faba NB |
1660 | .TP |
1661 | .B TestMessage | |
1662 | An array was found at startup, and the | |
7e23fc43 | 1663 | .B \-\-test |
98c6faba | 1664 | flag was given. |
773135f5 | 1665 | (syslog priority: Info) |
e0d19036 NB |
1666 | .RE |
1667 | ||
1668 | Only | |
98c6faba NB |
1669 | .B Fail , |
1670 | .B FailSpare , | |
1671 | .B DegradedArray , | |
d1732eeb | 1672 | .B SparesMissing , |
e0d19036 | 1673 | and |
98c6faba | 1674 | .B TestMessage |
e0d19036 NB |
1675 | cause Email to be sent. All events cause the program to be run. |
1676 | The program is run with two or three arguments, they being the event | |
1677 | name, the array device and possibly a second device. | |
1678 | ||
1679 | Each event has an associated array device (e.g. | |
1680 | .BR /dev/md1 ) | |
1681 | and possibly a second device. For | |
1682 | .BR Fail , | |
1683 | .BR FailSpare , | |
1684 | and | |
1685 | .B SpareActive | |
1686 | the second device is the relevant component device. | |
1687 | For | |
1688 | .B MoveSpare | |
1689 | the second device is the array that the spare was moved from. | |
1690 | ||
1691 | For | |
1692 | .B mdadm | |
1693 | to move spares from one array to another, the different arrays need to | |
1694 | be labelled with the same | |
1695 | .B spare-group | |
1696 | in the configuration file. The | |
1697 | .B spare-group | |
1698 | name can be any string. It is only necessary that different spare | |
2d465520 | 1699 | groups use different names. |
e0d19036 NB |
1700 | |
1701 | When | |
9a9dab36 | 1702 | .B mdadm |
e0d19036 NB |
1703 | detects that an array which is in a spare group has fewer active |
1704 | devices than necessary for the complete array, and has no spare | |
1705 | devices, it will look for another array in the same spare group that | |
1706 | has a full complement of working drive and a spare. It will then | |
1707 | attempt to remove the spare from the second drive and add it to the | |
1708 | first. | |
1709 | If the removal succeeds but the adding fails, then it is added back to | |
1710 | the original array. | |
1711 | ||
dd0781e5 NB |
1712 | .SH GROW MODE |
1713 | The GROW mode is used for changing the size or shape of an active | |
1714 | array. | |
1715 | For this to work, the kernel must support the necessary change. | |
2ae555c3 | 1716 | Various types of growth are being added during 2.6 development, |
dd0781e5 NB |
1717 | including restructuring a raid5 array to have more active devices. |
1718 | ||
dfd4d8ee NB |
1719 | Currently the only support available is to |
1720 | .IP \(bu 4 | |
1721 | change the "size" attribute | |
1722 | for RAID1, RAID5 and RAID6. | |
1723 | .IP \(bu 4 | |
00be0b12 | 1724 | increase the "raid-disks" attribute of RAID1, RAID5, and RAID6. |
dfd4d8ee | 1725 | .IP \(bu 4 |
2ae555c3 NB |
1726 | add a write-intent bitmap to any array which support these bitmaps, or |
1727 | remove a write-intent bitmap from such an array. | |
dfd4d8ee | 1728 | .PP |
dd0781e5 | 1729 | |
2ae555c3 | 1730 | .SS SIZE CHANGES |
fe80f49b | 1731 | Normally when an array is built the "size" it taken from the smallest |
dd0781e5 NB |
1732 | of the drives. If all the small drives in an arrays are, one at a |
1733 | time, removed and replaced with larger drives, then you could have an | |
1734 | array of large drives with only a small amount used. In this | |
1735 | situation, changing the "size" with "GROW" mode will allow the extra | |
1736 | space to start being used. If the size is increased in this way, a | |
1737 | "resync" process will start to make sure the new parts of the array | |
1738 | are synchronised. | |
1739 | ||
1740 | Note that when an array changes size, any filesystem that may be | |
1741 | stored in the array will not automatically grow to use the space. The | |
1742 | filesystem will need to be explicitly told to use the extra space. | |
1743 | ||
2ae555c3 NB |
1744 | .SS RAID-DEVICES CHANGES |
1745 | ||
dd0781e5 NB |
1746 | A RAID1 array can work with any number of devices from 1 upwards |
1747 | (though 1 is not very useful). There may be times which you want to | |
1748 | increase or decrease the number of active devices. Note that this is | |
1749 | different to hot-add or hot-remove which changes the number of | |
1750 | inactive devices. | |
1751 | ||
1752 | When reducing the number of devices in a RAID1 array, the slots which | |
1753 | are to be removed from the array must already be vacant. That is, the | |
1754 | devices that which were in those slots must be failed and removed. | |
1755 | ||
1756 | When the number of devices is increased, any hot spares that are | |
a9d69660 | 1757 | present will be activated immediately. |
dd0781e5 | 1758 | |
2ae555c3 NB |
1759 | Increasing the number of active devices in a RAID5 is much more |
1760 | effort. Every block in the array will need to be read and written | |
1761 | back to a new location. From 2.6.17, the Linux Kernel is able to do | |
1762 | this safely, including restart and interrupted "reshape". | |
1763 | ||
1764 | When relocating the first few stripes on a raid5, it is not possible | |
1765 | to keep the data on disk completely consistent and crash-proof. To | |
1766 | provide the required safety, mdadm disables writes to the array while | |
1767 | this "critical section" is reshaped, and takes a backup of the data | |
1768 | that is in that section. This backup is normally stored in any spare | |
1769 | devices that the array has, however it can also be stored in a | |
1770 | separate file specified with the | |
7e23fc43 | 1771 | .B \-\-backup\-file |
2ae555c3 NB |
1772 | option. If this option is used, and the system does crash during the |
1773 | critical period, the same file must be passed to | |
7e23fc43 | 1774 | .B \-\-assemble |
2ae555c3 NB |
1775 | to restore the backup and reassemble the array. |
1776 | ||
1777 | .SS BITMAP CHANGES | |
1778 | ||
1779 | A write-intent bitmap can be added to, or removed from, an active | |
1780 | array. Either internal bitmaps, or bitmaps stored in a separate file | |
fe80f49b NB |
1781 | can be added. Note that if you add a bitmap stored in a file which is |
1782 | in a filesystem that is on the raid array being affected, the system | |
1783 | will deadlock. The bitmap must be on a separate filesystem. | |
1784 | ||
8382f19b NB |
1785 | .SH INCREMENTAL MODE |
1786 | ||
1787 | .HP 12 | |
1788 | Usage: | |
7e23fc43 PS |
1789 | .B mdadm \-\-incremental |
1790 | .RB [ \-\-run ] | |
1791 | .RB [ \-\-quiet ] | |
8382f19b NB |
1792 | .I component-device |
1793 | .HP 12 | |
1794 | Usage: | |
7e23fc43 | 1795 | .B mdadm \-\-incremental \-\-rebuild |
8382f19b NB |
1796 | .HP 12 |
1797 | Usage: | |
7e23fc43 | 1798 | .B mdadm \-\-incremental \-\-run \-\-scan |
8382f19b NB |
1799 | |
1800 | ||
1801 | .PP | |
1802 | This mode is designed to be used in conjunction with a device | |
1803 | discovery system. As devices are found in a system, they can be | |
1804 | passed to | |
7e23fc43 | 1805 | .B "mdadm \-\-incremental" |
8382f19b NB |
1806 | to be conditionally added to an appropriate array. |
1807 | ||
1808 | .I mdadm | |
1809 | performs a number of tests to determine if the device is part of an | |
1810 | array, and which array is should be part of. If an appropriate array | |
1811 | is found, or can be created, | |
1812 | .I mdadm | |
1813 | adds the device to the array and conditionally starts the array. | |
1814 | ||
1815 | Note that | |
1816 | .I mdadm | |
1817 | will only add devices to an array which were previously working | |
1818 | (active or spare) parts of that array. It does not currently support | |
1819 | automatic inclusion of a new drive as a spare in some array. | |
1820 | ||
7e23fc43 | 1821 | .B "mdadm \-\-incremental" |
8382f19b NB |
1822 | requires a bug present in all kernels through 2.6.19, to be fixed. |
1823 | Hopefully this will be fixed in 2.6.20. Alternately apply the patch | |
1824 | which is included with the mdadm source distribution. If | |
1825 | .I mdadm | |
1826 | detects that this bug is present, it will abort any attempt to use | |
7e23fc43 | 1827 | .BR \-\-incremental . |
8382f19b NB |
1828 | |
1829 | The tests that | |
1830 | .I mdadm | |
1831 | makes are as follow: | |
1832 | .IP + | |
1833 | Is the device permitted by | |
1834 | .BR mdadm.conf ? | |
1835 | That is, is it listed in a | |
1836 | .B DEVICES | |
1837 | line in that file. If | |
1838 | .B DEVICES | |
1839 | is absent then the default it to allow any device. Similar if | |
1840 | .B DEVICES | |
1841 | contains the special word | |
1842 | .B partitions | |
1843 | then any device is allowed. Otherwise the device name given to | |
1844 | .I mdadm | |
1845 | must match one of the names or patterns in a | |
1846 | .B DEVICES | |
1847 | line. | |
1848 | ||
1849 | .IP + | |
1850 | Does the device have a valid md superblock. If a specific metadata | |
1851 | version is request with | |
7e23fc43 | 1852 | .B \-\-metadata |
8382f19b | 1853 | or |
7e23fc43 | 1854 | .B \-e |
8382f19b NB |
1855 | then only that style of metadata is accepted, otherwise |
1856 | .I mdadm | |
1857 | finds any known version of metadata. If no | |
1858 | .I md | |
1859 | metadata is found, the device is rejected. | |
1860 | ||
1861 | .IP + | |
1862 | Does the metadata match an expected array? | |
1863 | The metadata can match in two ways. Either there is an array listed | |
1864 | in | |
1865 | .B mdadm.conf | |
1866 | which identifies the array (either by UUID, by name, by device list, | |
1867 | or by minor-number), the array was created with a | |
1868 | .B homehost | |
1869 | specified, and that | |
1870 | .B homehost | |
1871 | matches that which is given in | |
1872 | .B mdadm.conf | |
1873 | or on the command line. | |
1874 | If | |
1875 | .I mdadm | |
1876 | is not able to positively identify the array as belonging to the | |
1877 | current host, the device will be rejected. | |
1878 | ||
1879 | .IP + | |
1880 | .I mdadm | |
1881 | keeps a list of arrays that is has partly assembled in | |
1882 | .B /var/run/mdadm/map | |
1883 | (or | |
1884 | .B /var/run/mdadm.map | |
1885 | if the directory doesn't exist). If no array exists which matches | |
1886 | the metadata on the new device, | |
1887 | .I mdadm | |
1888 | must choose a device name and unit number. It does this based on any | |
1889 | name given in | |
1890 | .B mdadm.conf | |
1891 | or any name information stored in the metadata. If this name | |
1892 | suggests a unit number, that number will be used, otherwise a free | |
1893 | unit number will be chosen. Normally | |
1894 | .I mdadm | |
1895 | will prefer to create a partitionable array, however if the | |
1896 | .B CREATE | |
1897 | line in | |
1898 | .B mdadm.conf | |
1899 | suggests that a non-partitionable array is preferred, that will be | |
1900 | honoured. | |
1901 | ||
1902 | .IP + | |
1903 | Once an appropriate array is found or created and the device is added, | |
1904 | .I mdadm | |
1905 | must decide if the array is ready to be started. It will | |
1906 | normally compare the number of available (non-spare) devices to the | |
1907 | number of devices that the metadata suggests need to be active. If | |
1908 | there are at least that many, the array will be started. This means | |
1909 | that if any devices are missing the array will not be restarted. | |
1910 | ||
1911 | As an alternative, | |
7e23fc43 | 1912 | .B \-\-run |
8382f19b NB |
1913 | may be passed to |
1914 | .B mdadm | |
1915 | in which case the array will be run as soon as there are enough | |
1916 | devices present for the data to be accessible. For a raid1, that | |
1917 | means one device will start the array. For a clean raid5, the array | |
1918 | will be started as soon as all but one drive is present. | |
1919 | ||
1920 | Note that neither of these approaches is really ideal. If it is can | |
1921 | be known that all device discovery has completed, then | |
1922 | .br | |
7e23fc43 | 1923 | .B " mdadm \-IRs" |
8382f19b NB |
1924 | .br |
1925 | can be run which will try to start all arrays that are being | |
1926 | incrementally assembled. They are started in "read-auto" mode in | |
1927 | which they are read-only until the first write request. This means | |
1928 | that no metadata updates are made and no attempt at resync or recovery | |
1929 | happens. Further devices that are found before the first write can | |
1930 | still be added safely. | |
1931 | ||
2d465520 NB |
1932 | .SH EXAMPLES |
1933 | ||
7e23fc43 | 1934 | .B " mdadm \-\-query /dev/name-of-device" |
2d465520 | 1935 | .br |
5787fa49 NB |
1936 | This will find out if a given device is a raid array, or is part of |
1937 | one, and will provide brief information about the device. | |
2d465520 | 1938 | |
7e23fc43 | 1939 | .B " mdadm \-\-assemble \-\-scan" |
2d465520 | 1940 | .br |
2ae555c3 | 1941 | This will assemble and start all arrays listed in the standard config file |
5787fa49 | 1942 | file. This command will typically go in a system startup file. |
2d465520 | 1943 | |
7e23fc43 | 1944 | .B " mdadm \-\-stop \-\-scan" |
5787fa49 NB |
1945 | .br |
1946 | This will shut down all array that can be shut down (i.e. are not | |
19f8b8fc | 1947 | currently in use). This will typically go in a system shutdown script. |
2d465520 | 1948 | |
7e23fc43 | 1949 | .B " mdadm \-\-follow \-\-scan \-\-delay=120" |
2d465520 | 1950 | .br |
5787fa49 NB |
1951 | If (and only if) there is an Email address or program given in the |
1952 | standard config file, then | |
1953 | monitor the status of all arrays listed in that file by | |
1954 | polling them ever 2 minutes. | |
2d465520 | 1955 | |
7e23fc43 | 1956 | .B " mdadm \-\-create /dev/md0 \-\-level=1 \-\-raid\-devices=2 /dev/hd[ac]1" |
2d465520 | 1957 | .br |
5787fa49 | 1958 | Create /dev/md0 as a RAID1 array consisting of /dev/hda1 and /dev/hdc1. |
2d465520 | 1959 | |
2d465520 | 1960 | .br |
7e23fc43 | 1961 | .B " echo 'DEVICE /dev/hd*[0\-9] /dev/sd*[0\-9]' > mdadm.conf" |
2d465520 | 1962 | .br |
7e23fc43 | 1963 | .B " mdadm \-\-detail \-\-scan >> mdadm.conf" |
2d465520 | 1964 | .br |
5787fa49 NB |
1965 | This will create a prototype config file that describes currently |
1966 | active arrays that are known to be made from partitions of IDE or SCSI drives. | |
2d465520 NB |
1967 | This file should be reviewed before being used as it may |
1968 | contain unwanted detail. | |
1969 | ||
7e23fc43 | 1970 | .B " echo 'DEVICE /dev/hd[a\-z] /dev/sd*[a\-z]' > mdadm.conf" |
2d465520 | 1971 | .br |
7e23fc43 | 1972 | .B " mdadm \-\-examine \-\-scan \-\-config=mdadm.conf >> mdadm.conf" |
5787fa49 | 1973 | .ber |
2ae555c3 | 1974 | This will find what arrays could be assembled from existing IDE and |
5787fa49 NB |
1975 | SCSI whole drives (not partitions) and store the information is the |
1976 | format of a config file. | |
2d465520 NB |
1977 | This file is very likely to contain unwanted detail, particularly |
1978 | the | |
1979 | .B devices= | |
5787fa49 NB |
1980 | entries. It should be reviewed and edited before being used as an |
1981 | actual config file. | |
2d465520 | 1982 | |
7e23fc43 | 1983 | .B " mdadm \-\-examine \-\-brief \-\-scan \-\-config=partitions" |
2d465520 | 1984 | .br |
7e23fc43 | 1985 | .B " mdadm \-Ebsc partitions" |
5787fa49 NB |
1986 | .br |
1987 | Create a list of devices by reading | |
1988 | .BR /proc/partitions , | |
1989 | scan these for RAID superblocks, and printout a brief listing of all | |
1990 | that was found. | |
2d465520 | 1991 | |
7e23fc43 | 1992 | .B " mdadm \-Ac partitions \-m 0 /dev/md0" |
2d465520 | 1993 | .br |
5787fa49 NB |
1994 | Scan all partitions and devices listed in |
1995 | .BR /proc/partitions | |
1996 | and assemble | |
1997 | .B /dev/md0 | |
1998 | out of all such devices with a RAID superblock with a minor number of 0. | |
2d465520 | 1999 | |
7e23fc43 | 2000 | .B " mdadm \-\-monitor \-\-scan \-\-daemonise > /var/run/mdadm" |
d013a55e NB |
2001 | .br |
2002 | If config file contains a mail address or alert program, run mdadm in | |
2003 | the background in monitor mode monitoring all md devices. Also write | |
2004 | pid of mdadm daemon to | |
2005 | .BR /var/run/mdadm . | |
2006 | ||
7e23fc43 | 2007 | .B " mdadm \-Iq /dev/somedevice" |
8382f19b NB |
2008 | .br |
2009 | Try to incorporate newly discovered device into some array as | |
2010 | appropriate. | |
2011 | ||
7e23fc43 | 2012 | .B " mdadm \-\-incremental \-\-rebuild \-\-run \-\-scan" |
8382f19b NB |
2013 | .br |
2014 | Rebuild the array map from any current arrays, and then start any that | |
2015 | can be started. | |
2016 | ||
b80da661 NB |
2017 | .B " mdadm /dev/md4 --fail detached --remove detached" |
2018 | .br | |
2019 | Any devices which are components of /dev/md4 will be marked as faulty | |
2020 | and then remove from the array. | |
2021 | ||
7e23fc43 | 2022 | .B " mdadm \-\-create \-\-help" |
2d465520 | 2023 | .br |
2ae555c3 | 2024 | Provide help about the Create mode. |
2d465520 | 2025 | |
7e23fc43 | 2026 | .B " mdadm \-\-config \-\-help" |
5787fa49 NB |
2027 | .br |
2028 | Provide help about the format of the config file. | |
2d465520 | 2029 | |
7e23fc43 | 2030 | .B " mdadm \-\-help" |
5787fa49 NB |
2031 | .br |
2032 | Provide general help. | |
cd29a5c8 | 2033 | |
cd29a5c8 NB |
2034 | |
2035 | .SH FILES | |
2036 | ||
2037 | .SS /proc/mdstat | |
2038 | ||
2ae555c3 NB |
2039 | If you're using the |
2040 | .B /proc | |
cd29a5c8 NB |
2041 | filesystem, |
2042 | .B /proc/mdstat | |
2d465520 NB |
2043 | lists all active md devices with information about them. |
2044 | .B mdadm | |
2045 | uses this to find arrays when | |
7e23fc43 | 2046 | .B \-\-scan |
2d465520 NB |
2047 | is given in Misc mode, and to monitor array reconstruction |
2048 | on Monitor mode. | |
2049 | ||
cd29a5c8 | 2050 | |
9a9dab36 | 2051 | .SS /etc/mdadm.conf |
cd29a5c8 | 2052 | |
11a3e71d NB |
2053 | The config file lists which devices may be scanned to see if |
2054 | they contain MD super block, and gives identifying information | |
2055 | (e.g. UUID) about known MD arrays. See | |
2056 | .BR mdadm.conf (5) | |
2057 | for more details. | |
cd29a5c8 | 2058 | |
8382f19b NB |
2059 | .SS /var/run/mdadm/map |
2060 | When | |
7e23fc43 | 2061 | .B \-\-incremental |
8382f19b NB |
2062 | mode is used. this file gets a list of arrays currently being created. |
2063 | If | |
2064 | .B /var/run/mdadm | |
2065 | does not exist as a directory, then | |
2066 | .B /var/run/mdadm.map | |
2067 | is used instead. | |
2068 | ||
48f7b27a NB |
2069 | .SH DEVICE NAMES |
2070 | ||
2071 | While entries in the /dev directory can have any format you like, | |
2072 | .I mdadm | |
2073 | has an understanding of 'standard' formats which it uses to guide its | |
2074 | behaviour when creating device files via the | |
7e23fc43 | 2075 | .B \-\-auto |
48f7b27a NB |
2076 | option. |
2077 | ||
2078 | The standard names for non-partitioned arrays (the only sort of md | |
2079 | array available in 2.4 and earlier) either of | |
2080 | .IP | |
2081 | /dev/mdNN | |
2082 | .br | |
2083 | /dev/md/NN | |
2084 | .PP | |
2085 | where NN is a number. | |
2086 | The standard names for partitionable arrays (as available from 2.6 | |
2087 | onwards) is one of | |
2088 | .IP | |
2089 | /dev/md/dNN | |
2090 | .br | |
2091 | /dev/md_dNN | |
2092 | .PP | |
2093 | Partition numbers should be indicated by added "pMM" to these, thus "/dev/md/d1p2". | |
52826846 | 2094 | |
2d465520 NB |
2095 | .SH NOTE |
2096 | .B mdadm | |
2097 | was previously known as | |
2098 | .BR mdctl . | |
a9d69660 NB |
2099 | .P |
2100 | .B mdadm | |
2101 | is completely separate from the | |
2102 | .B raidtools | |
2103 | package, and does not use the | |
2104 | .I /etc/raidtab | |
2105 | configuration file at all. | |
2106 | ||
52826846 | 2107 | .SH SEE ALSO |
cd29a5c8 NB |
2108 | For information on the various levels of |
2109 | RAID, check out: | |
2110 | ||
2111 | .IP | |
7e23fc43 PS |
2112 | .UR http://ostenfeld.dk/~jakob/Software\-RAID.HOWTO/ |
2113 | http://ostenfeld.dk/~jakob/Software\-RAID.HOWTO/ | |
cd29a5c8 | 2114 | .UE |
a9d69660 NB |
2115 | '''.PP |
2116 | '''for new releases of the RAID driver check out: | |
2117 | ''' | |
2118 | '''.IP | |
2119 | '''.UR ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches | |
2120 | '''ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches | |
2121 | '''.UE | |
2122 | '''.PP | |
2123 | '''or | |
2124 | '''.IP | |
2125 | '''.UR http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ | |
2126 | '''http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ | |
2127 | '''.UE | |
cd29a5c8 | 2128 | .PP |
2ae555c3 | 2129 | The latest version of |
a9d69660 NB |
2130 | .I mdadm |
2131 | should always be available from | |
cd29a5c8 | 2132 | .IP |
a9d69660 NB |
2133 | .UR http://www.kernel.org/pub/linux/utils/raid/mdadm/ |
2134 | http://www.kernel.org/pub/linux/utils/raid/mdadm/ | |
cd29a5c8 NB |
2135 | .UE |
2136 | .PP | |
a9d69660 NB |
2137 | .IR mdadm.conf (5), |
2138 | .IR md (4). | |
56eb10c0 | 2139 | .PP |
52826846 NB |
2140 | .IR raidtab (5), |
2141 | .IR raid0run (8), | |
2142 | .IR raidstop (8), | |
a9d69660 | 2143 | .IR mkraid (8). |