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52826846 | 1 | .\" -*- nroff -*- |
e0d19036 | 2 | .TH MDADM 8 |
52826846 | 3 | .SH NAME |
9a9dab36 | 4 | mdadm \- manage MD devices |
cd29a5c8 NB |
5 | .I aka |
6 | Linux Software Raid. | |
7 | ||
52826846 NB |
8 | .SH SYNOPSIS |
9 | ||
e0d19036 | 10 | .BI mdadm " [mode] <raiddevice> [options] <component-devices>" |
52826846 NB |
11 | |
12 | .SH DESCRIPTION | |
13 | RAID devices are virtual devices created from two or more | |
cd29a5c8 NB |
14 | real block devices. This allows multiple devices (typically disk |
15 | drives or partitions there-of) to be combined into a single device to | |
16 | hold (for example) a single filesystem. | |
17 | Some RAID levels included redundancy and so can survive some degree of | |
18 | device failure. | |
19 | ||
20 | Linux Software RAID devices are implemented through the md (Multiple Devices) device driver. | |
21 | ||
22 | Currently, Linux supports | |
23 | .B LINEAR | |
24 | md devices, | |
25 | .B RAID0 | |
26 | (striping), | |
27 | .B RAID1 | |
28 | (mirroring), | |
29 | .B RAID4 | |
30 | and | |
31 | .B RAID5. | |
32 | ||
33 | Recent kernels (2002) also support a mode known as | |
34 | .BR MULTIPATH . | |
9a9dab36 | 35 | .B mdadm |
e0d19036 | 36 | only provides limited support for MULTIPATH as yet. |
52826846 | 37 | |
9a9dab36 | 38 | .B mdadm |
11a3e71d NB |
39 | is a program that can be used to create, manage, and monitor |
40 | MD devices. As | |
cd29a5c8 NB |
41 | such it provides a similar set of functionality to the |
42 | .B raidtools | |
43 | packages. | |
44 | The key differences between | |
9a9dab36 | 45 | .B mdadm |
cd29a5c8 NB |
46 | and |
47 | .B raidtools | |
48 | are: | |
49 | .IP \(bu 4 | |
9a9dab36 | 50 | .B mdadm |
cd29a5c8 NB |
51 | is a single program and not a collection of programs. |
52 | .IP \(bu 4 | |
9a9dab36 | 53 | .B mdadm |
cd29a5c8 | 54 | can perform (almost) all of its functions without having a |
9a9dab36 | 55 | configuration file. Also mdadm helps with management of the configuration |
cd29a5c8 NB |
56 | file. |
57 | .IP \(bu 4 | |
9a9dab36 | 58 | .B mdadm |
e0d19036 | 59 | can provide information about your arrays (through Query, Detail, and Examine) |
cd29a5c8 NB |
60 | that |
61 | .B raidtools | |
62 | cannot. | |
52826846 NB |
63 | |
64 | .SH MODES | |
e0d19036 | 65 | mdadm has 6 major modes of operation: |
cd29a5c8 NB |
66 | .TP |
67 | .B Assemble | |
68 | Assemble the parts of a previously created | |
52826846 NB |
69 | array into an active array. Components can be explicitly given |
70 | or can be searched for. | |
9a9dab36 | 71 | .B mdadm |
cd29a5c8 NB |
72 | checks that the components |
73 | do form a bona fide array, and can, on request, fiddle superblock | |
74 | information so as to assemble a faulty array. | |
75 | ||
76 | .TP | |
77 | .B Build | |
78 | Build a legacy array without per-device superblocks. | |
79 | ||
80 | .TP | |
81 | .B Create | |
82 | Create a new array with per-device superblocks. | |
83 | '''It can progress | |
84 | '''in several step create-add-add-run or it can all happen with one command. | |
85 | ||
86 | .TP | |
e0d19036 NB |
87 | .B Manage |
88 | This is for doing things to specific components of an array such as | |
89 | adding new spares and removing faulty devices. | |
cd29a5c8 NB |
90 | |
91 | .TP | |
e0d19036 NB |
92 | .B Misc |
93 | This mode allows operations on independent devices such as examine MD | |
94 | superblocks, erasing old superblocks and stopping active arrays. | |
cd29a5c8 NB |
95 | |
96 | .TP | |
97 | .B "Follow or Monitor" | |
98 | Monitor one or more md devices and act on any state changes. | |
99 | ||
52826846 NB |
100 | .SH OPTIONS |
101 | ||
102 | Available options are: | |
103 | ||
cd29a5c8 NB |
104 | .TP |
105 | .BR -A ", " --assemble | |
106 | Assemble an existing array. | |
52826846 | 107 | |
cd29a5c8 NB |
108 | .TP |
109 | .BR -B ", " --build | |
110 | Build a legacy array without superblocks. | |
52826846 | 111 | |
cd29a5c8 NB |
112 | .TP |
113 | .BR -C ", " --create | |
114 | Create a new array. | |
52826846 | 115 | |
e0d19036 NB |
116 | .TP |
117 | .BR -Q ", " --query | |
118 | Examine a device to see | |
119 | (1) if it is an md device and (2) if it is a component of an md | |
120 | array. | |
121 | Information about what is discovered is presented. | |
122 | ||
cd29a5c8 NB |
123 | .TP |
124 | .BR -D ", " --detail | |
125 | Print detail of one or more md devices. | |
52826846 | 126 | |
cd29a5c8 NB |
127 | .TP |
128 | .BR -E ", " --examine | |
129 | Print content of md superblock on device(s). | |
52826846 | 130 | |
cd29a5c8 NB |
131 | .TP |
132 | .BR -F ", " --follow ", " --monitor | |
133 | Select | |
134 | .B Monitor | |
135 | mode. | |
52826846 | 136 | |
cd29a5c8 NB |
137 | .TP |
138 | .BR -h ", " --help | |
139 | Display help message or, after above option, mode specific help message. | |
52826846 | 140 | |
cd29a5c8 NB |
141 | .TP |
142 | .BR -V ", " --version | |
9a9dab36 | 143 | Print version information for mdadm. |
52826846 | 144 | |
cd29a5c8 NB |
145 | .TP |
146 | .BR -v ", " --verbose | |
147 | Be more verbose about what is happening. | |
52826846 | 148 | |
cd29a5c8 NB |
149 | .TP |
150 | .BR -b ", " --brief | |
151 | Be less verbose. This is used with | |
152 | .B --detail | |
153 | and | |
154 | .BR --examine . | |
52826846 | 155 | |
e0d19036 NB |
156 | .TP |
157 | .BR -f ", " --force | |
158 | Be more forceful about certain operations. See the various modes of | |
159 | the exact meaning of this option in different contexts. | |
160 | ||
161 | .TP | |
162 | .BR -c ", " --config= | |
163 | Specify the config file. Default is | |
164 | .BR /etc/mdadm.conf . | |
165 | ||
166 | .TP | |
167 | .BR -s ", " --scan | |
168 | scan config file or | |
169 | .B /proc/mdstat | |
170 | for missing information. | |
171 | In general, this option gives | |
172 | .B mdadm | |
173 | permission to get any missing information, like component devices, | |
174 | array devices, array identities, and alert destination from the | |
175 | configuration file: | |
176 | .BR /etc/mdadm.conf . | |
177 | One exception is MISC mode when using | |
178 | .B --detail | |
179 | or | |
180 | .B --stop | |
181 | in which case | |
182 | .B --scan | |
183 | says to get a list of array devices from | |
184 | .BR /proc/mdstat . | |
185 | ||
cd29a5c8 | 186 | .SH For create or build: |
52826846 | 187 | |
cd29a5c8 NB |
188 | .TP |
189 | .BR -c ", " --chunk= | |
190 | Specify chunk size of kibibytes. The default is 64. | |
52826846 | 191 | |
cd29a5c8 NB |
192 | .TP |
193 | .BR --rounding= | |
194 | Specify rounding factor for linear array (==chunk size) | |
52826846 | 195 | |
cd29a5c8 NB |
196 | .TP |
197 | .BR -l ", " --level= | |
198 | Set raid level. Options are: linear, raid0, 0, stripe, raid1, 1, mirror, raid5, 4, | |
c913b90e | 199 | raid5, 5, multipath, mp. Obviously some of these are synonymous. |
cd29a5c8 | 200 | Only the first 4 are valid when Building. |
52826846 | 201 | |
cd29a5c8 NB |
202 | .TP |
203 | .BR -p ", " --parity= | |
204 | Set raid5 parity algorithm. Options are: | |
205 | {left,right}-{,a}symmetric, la, ra, ls, rs. The default is left-symmetric. | |
52826846 | 206 | |
cd29a5c8 NB |
207 | .TP |
208 | .BR --layout= | |
209 | same as --parity | |
52826846 | 210 | |
cd29a5c8 | 211 | .TP |
b83d95f3 | 212 | .BR -n ", " --raid-devices= |
cd29a5c8 NB |
213 | number of active devices in array. |
214 | ||
215 | .TP | |
b83d95f3 NB |
216 | .BR -x ", " --spare-devices= |
217 | number of spare (eXtra) devices in initial array. Spares can be added | |
cd29a5c8 NB |
218 | and removed later. |
219 | ||
220 | .TP | |
221 | .BR -z ", " --size= | |
222 | Amount (in Kibibytes) of space to use from each drive in RAID1/4/5. | |
223 | This must be a multiple of the chunk size, and must leave about 128Kb | |
224 | of space at the end of the drive for the RAID superblock. | |
225 | If this is not specified | |
226 | (as it normally is not) the smallest drive (or partition) sets the | |
227 | size, though if there is a variance among the drives of greater than 1%, a warning is | |
228 | issued. | |
52826846 NB |
229 | |
230 | .SH For assemble: | |
231 | ||
cd29a5c8 NB |
232 | .TP |
233 | .BR -u ", " --uuid= | |
234 | uuid of array to assemble. Devices which don't have this uuid are | |
235 | excluded | |
236 | ||
237 | .TP | |
238 | .BR -m ", " --super-minor= | |
239 | Minor number of device that array was created for. Devices which | |
240 | don't have this minor number are excluded. If you create an array as | |
241 | /dev/md1, then all superblock will contain the minor number 1, even if | |
242 | the array is later assembled as /dev/md2. | |
243 | ||
cd29a5c8 NB |
244 | .TP |
245 | .BR -f ", " --force | |
52826846 NB |
246 | Assemble the array even if some superblocks appear out-of-date |
247 | ||
cd29a5c8 NB |
248 | .TP |
249 | .BR -R ", " --run | |
250 | Attempt to start the array even if fewer drives were given than are | |
251 | needed for a full array. Normally if not all drives are found and | |
252 | .B --scan | |
253 | is not used, then the array will be assembled but not started. | |
254 | With | |
255 | .B --run | |
256 | an attempt will be made to start it anyway. | |
52826846 | 257 | |
e0d19036 | 258 | .SH For Manage mode: |
52826846 | 259 | |
cd29a5c8 NB |
260 | .TP |
261 | .BR -a ", " --add | |
262 | '''add, or | |
263 | hotadd listed devices. | |
52826846 | 264 | |
cd29a5c8 NB |
265 | .TP |
266 | .BR -r ", " --remove | |
267 | remove listed devices. The must not be active. i.e. they should | |
268 | be failed or spare devices. | |
52826846 | 269 | |
cd29a5c8 NB |
270 | .TP |
271 | .BR -f ", " --fail | |
272 | mark listed devices as faulty. | |
52826846 | 273 | |
cd29a5c8 NB |
274 | .TP |
275 | .BR --set-faulty | |
276 | same as --fail. | |
52826846 | 277 | |
e0d19036 NB |
278 | .SH For Misc mode: |
279 | ||
cd29a5c8 NB |
280 | .TP |
281 | .BR -R ", " --run | |
282 | start a partially built array. | |
52826846 | 283 | |
cd29a5c8 NB |
284 | .TP |
285 | .BR -S ", " --stop | |
286 | deactivate array, releasing all resources. | |
52826846 | 287 | |
cd29a5c8 NB |
288 | .TP |
289 | .BR -o ", " --readonly | |
290 | mark array as readonly. | |
52826846 | 291 | |
cd29a5c8 NB |
292 | .TP |
293 | .BR -w ", " --readwrite | |
294 | mark array as readwrite. | |
52826846 | 295 | |
e0d19036 NB |
296 | .TP |
297 | .B --zero-superblock | |
298 | If the device contains a valid md superblock, the block is | |
299 | over-written with zeros. With | |
300 | --force | |
301 | the block where the superblock would be is over-written even if it | |
302 | doesn't appear to be valid. | |
52826846 | 303 | |
e0d19036 NB |
304 | .SH For Monitor mode: |
305 | .TP | |
306 | .BR -m ", " --mail | |
307 | Give a mail address to send alerts to. | |
308 | ||
309 | .TP | |
310 | .BR -p ", " --program ", " --alert | |
311 | Give a program to be run whenever an event is detected. | |
312 | ||
313 | .TP | |
314 | .BR -d ", " --delay | |
315 | Give a delay in seconds. | |
316 | .B mdadm | |
317 | polls the md arrays and then waits this many seconds before polling | |
318 | again. The default is 60 seconds. | |
319 | ||
320 | .SH ASSEMBLE MODE | |
52826846 | 321 | |
cd29a5c8 NB |
322 | .HP 12 |
323 | Usage: | |
9a9dab36 | 324 | .B mdadm --assemble |
cd29a5c8 NB |
325 | .I device options... |
326 | .HP 12 | |
327 | Usage: | |
9a9dab36 | 328 | .B mdadm --assemble --scan |
cd29a5c8 | 329 | .I options... |
52826846 | 330 | |
cd29a5c8 | 331 | .PP |
52826846 | 332 | This usage assembles one or more raid arrays from pre-existing components. |
9a9dab36 | 333 | For each array, mdadm needs to know the md device, the identity of the |
e0d19036 | 334 | array, and a number of component-devices. These can be found in a number of ways. |
52826846 NB |
335 | |
336 | The md device is either given before | |
337 | .B --scan | |
338 | or is found from the config file. In the latter case, multiple md devices | |
9a9dab36 | 339 | can be started with a single mdadm command. |
52826846 | 340 | |
cd29a5c8 | 341 | The identity can be given with the |
52826846 | 342 | .B --uuid |
cd29a5c8 NB |
343 | option, with the |
344 | .B --super-minor | |
345 | option, can be found in in the config file, or will be taken from the | |
e0d19036 | 346 | super block on the first component-device listed on the command line. |
52826846 NB |
347 | |
348 | Devices can be given on the | |
349 | .B --assemble | |
cd29a5c8 NB |
350 | command line or from the config file. Only devices which have an md |
351 | superblock which contains the right identity will be considered for any device. | |
52826846 NB |
352 | |
353 | The config file is only used if explicitly named with | |
354 | .B --config | |
355 | or requested with | |
356 | .B --scan. | |
357 | In the later case, | |
9a9dab36 | 358 | .B /etc/mdadm.conf |
52826846 NB |
359 | is used. |
360 | ||
361 | If | |
362 | .B --scan | |
cd29a5c8 NB |
363 | is not given, then the config file will only be used to find the |
364 | identity of md arrays. | |
52826846 | 365 | |
cd29a5c8 NB |
366 | Normally the array will be started after it is assembled. However is |
367 | .B --scan | |
368 | is not given and insufficient drives were lists to start a complete | |
369 | (non-degraded) array, then the array is not started (to guard against | |
370 | usage errors). To insist that the array be started in this case (as | |
371 | may work for RAID1 or RAID5), give the | |
372 | .B --run | |
373 | flag. | |
52826846 | 374 | |
52826846 | 375 | |
cd29a5c8 | 376 | .SH BUILD MODE |
52826846 | 377 | |
cd29a5c8 NB |
378 | .HP 12 |
379 | Usage: | |
9a9dab36 | 380 | .B mdadm --build |
cd29a5c8 NB |
381 | .I device |
382 | .BI --chunk= X | |
383 | .BI --level= Y | |
b83d95f3 | 384 | .BI --raid-devices= Z |
cd29a5c8 NB |
385 | .I devices |
386 | ||
387 | .PP | |
52826846 | 388 | This usage is similar to |
cd29a5c8 | 389 | .BR --create . |
52826846 | 390 | The difference is that it creates a legacy array without a superblock. With |
cd29a5c8 | 391 | these arrays there is no difference between initially creating the array and |
52826846 NB |
392 | subsequently assembling the array, except that hopefully there is useful |
393 | data there in the second case. | |
394 | ||
cd29a5c8 NB |
395 | The level may only be 0, raid0, or linear. All devices must be listed |
396 | and the array will be started once complete. | |
397 | ||
398 | .SH CREATE MODE | |
399 | ||
400 | .HP 12 | |
401 | Usage: | |
9a9dab36 | 402 | .B mdadm --create |
cd29a5c8 NB |
403 | .I device |
404 | .BI --chunk= X | |
405 | .BI --level= Y | |
406 | .br | |
b83d95f3 | 407 | .BI --raid-devices= Z |
cd29a5c8 NB |
408 | .I devices |
409 | ||
410 | .PP | |
411 | This usage will initialise a new md array, associate some devices with | |
412 | it, and activate the array. | |
413 | ||
414 | As devices are added, they are checked to see if they contain raid | |
415 | superblocks or filesystems. They are also check to see if the variance in | |
416 | device size exceeds 1%. | |
417 | ||
418 | If any discrepancy is found, the array will not automatically be run, though | |
419 | the presence of a | |
420 | .B --run | |
421 | can override this caution. | |
422 | ||
423 | '''If the | |
424 | '''.B --size | |
e0d19036 | 425 | '''option is given, it is not necessary to list any component-devices in this command. |
cd29a5c8 NB |
426 | '''They can be added later, before a |
427 | '''.B --run. | |
428 | '''If no | |
429 | '''.B --size | |
430 | '''is given, the apparent size of the smallest drive given is used. | |
431 | ||
432 | The General Management options that are valid with --create are: | |
433 | .TP | |
434 | .B --run | |
435 | insist of running the array even if some devices look like they might | |
436 | be in use. | |
437 | ||
438 | .TP | |
439 | .B --readonly | |
440 | start the array readonly - not supported yet. | |
52826846 | 441 | |
e0d19036 | 442 | .SH MANAGE MODE |
cd29a5c8 NB |
443 | .HP 12 |
444 | Usage: | |
e0d19036 NB |
445 | .B mdadm |
446 | .I device | |
447 | .I options... devices... | |
cd29a5c8 NB |
448 | .PP |
449 | ||
e0d19036 NB |
450 | This usage will allow individual devices in an array to be failed, |
451 | removed or added. It is possible to perform multiple operations with | |
452 | on command. For example: | |
453 | .br | |
454 | mdadm /dev/md0 -f /dev/hda1 -r /dev/hda1 /a /dev/hda1 | |
455 | .br | |
456 | will firstly mark | |
457 | .B /dev/hda1 | |
458 | as faulty in | |
459 | .B /dev/md0 | |
460 | and will then remove it from the array and finally add it back | |
461 | in as a spare. However only one md array can be affect by a single | |
462 | command. | |
463 | ||
464 | .SH MISC MODE | |
465 | .HP 12 | |
466 | Usage: | |
9a9dab36 | 467 | .B mdadm |
e0d19036 NB |
468 | .I options ... |
469 | .I devices ... | |
470 | .PP | |
cd29a5c8 | 471 | |
e0d19036 NB |
472 | MISC mode includes a number if distinct operations that |
473 | operate on distinct devices. The operations are: | |
474 | .TP | |
475 | --query | |
476 | The device is examined to see if it is | |
477 | (1) an active md array, or | |
478 | (2) a component of an md array. | |
479 | The information discovered is reported. | |
480 | ||
481 | .TP | |
482 | --detail | |
483 | The device should be an active md device. mdadm will display | |
484 | a detailed description of the array. | |
cd29a5c8 | 485 | .B --brief |
e0d19036 NB |
486 | will cause the output to be less detailed and format to be |
487 | suitable for inclusion in | |
9a9dab36 | 488 | .BR /etc/mdadm.conf . |
cd29a5c8 | 489 | |
e0d19036 NB |
490 | .TP |
491 | --examine | |
492 | The device should be a component of an md array. mdadm will | |
493 | read the md superblock of the device and display the contents. | |
494 | If | |
495 | .B --brief | |
496 | is given, or | |
497 | .B --scan | |
498 | then multiple devices that are components of the one array | |
499 | are grouped together and reported in a single entry suitable | |
500 | for inclusion in | |
501 | .BR /etc/mdadm.conf . | |
502 | ||
503 | Have | |
504 | .B --scan | |
505 | without listing any devices will cause all devices listed in the | |
506 | config file to be examined. | |
507 | ||
508 | .TP | |
509 | --stop | |
510 | This devices should active md arrays which will be deactivated, if | |
511 | they are not currently in use. | |
512 | ||
513 | .TP | |
514 | --run | |
515 | This will fully activate a partially assembled md array. | |
516 | ||
517 | .TP | |
518 | --readonly | |
519 | This will mark an active array as read-only, providing that it is | |
520 | not currently being used. | |
521 | ||
522 | .TP | |
523 | --readwrite | |
524 | This will change a | |
525 | .B readonly | |
526 | array back to being read/write. | |
527 | ||
528 | .SH MONITOR MODE | |
529 | ||
cd29a5c8 NB |
530 | .HP 12 |
531 | Usage: | |
e0d19036 NB |
532 | .B mdadm --monitor |
533 | .I options... devices... | |
534 | ||
cd29a5c8 | 535 | .PP |
e0d19036 NB |
536 | This usage causes |
537 | .B mdadm | |
538 | to periodically poll a number of md arrays and to report on any events | |
539 | noticed. | |
540 | .B mdadm | |
541 | will never exit once it decides that there are arrays to be checked, | |
542 | so it should normally be run in the background. | |
543 | ||
544 | If any devices are listed on the command line, | |
545 | .B mdadm | |
546 | will only monitor those devices. Otherwise all arrays listed in the | |
547 | configuration file will be monitored. Further, if | |
548 | .B --scan | |
549 | is given, then any other md devices that appear in | |
550 | .B /proc/mdstat | |
551 | will also be monitored. | |
552 | ||
553 | The result of monitoring the arrays is the generation of events. | |
554 | These events are passed to a separate program (is specified) and may | |
555 | be mail to a given E-mail address. | |
556 | ||
cd29a5c8 NB |
557 | |
558 | If | |
559 | .B --scan | |
e0d19036 NB |
560 | is given, then a program or an E-mail address must be specified on the |
561 | command line or in the config file. If neither are available, then | |
562 | .B mdadm | |
563 | will not monitor anything. | |
564 | Without | |
cd29a5c8 | 565 | .B --scan |
e0d19036 NB |
566 | .B mdadm |
567 | will continue monitoring along as something was found to monitor. If | |
568 | no program or email is given, then each event is reported to | |
569 | .BR stdout . | |
cd29a5c8 | 570 | |
e0d19036 NB |
571 | The different events are: |
572 | ||
573 | .RS 4 | |
574 | .TP | |
575 | .B DeviceDisappeared | |
576 | An md array which previously was configured appear to no longer be | |
577 | configured. | |
578 | ||
579 | .TP | |
580 | .B RebuildStarted | |
581 | An md array started reconstruction. | |
582 | ||
583 | .TP | |
584 | .BI Rebuild NN | |
585 | Where | |
586 | .I NN | |
587 | is 20, 40, 60, or 80, this indicates that rebuild has passed that many | |
588 | percentage of the total. | |
589 | ||
590 | .TP | |
591 | .B Fail | |
592 | An active component device of an array has been marked as faulty. | |
593 | ||
594 | .TP | |
595 | .B FailSpare | |
596 | A spare component device which was being rebuilt to replace a faulty | |
597 | device has failed. | |
598 | ||
599 | .TP | |
600 | .B SpareActive | |
601 | A spare component device which was being rebuilt to replace a faulty | |
602 | device as been successfully rebuild and has been made active. | |
603 | ||
604 | .TP | |
605 | .B NewArray | |
606 | A new md array has been detected in the | |
607 | .B /proc/mdstat | |
608 | file. | |
609 | ||
610 | .TP | |
611 | .B MoveSpare | |
612 | A spare drive has been moved from one array in a | |
613 | .B spare-group | |
614 | to another to allow a failed drive to be replaced. | |
615 | ||
616 | .RE | |
617 | ||
618 | Only | |
619 | .B Fail | |
620 | and | |
621 | .B FailSpare | |
622 | cause Email to be sent. All events cause the program to be run. | |
623 | The program is run with two or three arguments, they being the event | |
624 | name, the array device and possibly a second device. | |
625 | ||
626 | Each event has an associated array device (e.g. | |
627 | .BR /dev/md1 ) | |
628 | and possibly a second device. For | |
629 | .BR Fail , | |
630 | .BR FailSpare , | |
631 | and | |
632 | .B SpareActive | |
633 | the second device is the relevant component device. | |
634 | For | |
635 | .B MoveSpare | |
636 | the second device is the array that the spare was moved from. | |
637 | ||
638 | For | |
639 | .B mdadm | |
640 | to move spares from one array to another, the different arrays need to | |
641 | be labelled with the same | |
642 | .B spare-group | |
643 | in the configuration file. The | |
644 | .B spare-group | |
645 | name can be any string. It is only necessary that different spare | |
646 | groups use different name. | |
647 | ||
648 | When | |
9a9dab36 | 649 | .B mdadm |
e0d19036 NB |
650 | detects that an array which is in a spare group has fewer active |
651 | devices than necessary for the complete array, and has no spare | |
652 | devices, it will look for another array in the same spare group that | |
653 | has a full complement of working drive and a spare. It will then | |
654 | attempt to remove the spare from the second drive and add it to the | |
655 | first. | |
656 | If the removal succeeds but the adding fails, then it is added back to | |
657 | the original array. | |
658 | ||
cd29a5c8 NB |
659 | |
660 | '''.SH BUGS | |
661 | '''no known bugs. | |
662 | ||
663 | .SH FILES | |
664 | ||
665 | .SS /proc/mdstat | |
666 | ||
667 | If you're using the | |
668 | .B /proc | |
669 | filesystem, | |
670 | .B /proc/mdstat | |
671 | gives you informations about md devices status. | |
672 | This file is not currently used by | |
9a9dab36 | 673 | .BR mdadm . |
cd29a5c8 | 674 | |
9a9dab36 | 675 | .SS /etc/mdadm.conf |
cd29a5c8 | 676 | |
11a3e71d NB |
677 | The config file lists which devices may be scanned to see if |
678 | they contain MD super block, and gives identifying information | |
679 | (e.g. UUID) about known MD arrays. See | |
680 | .BR mdadm.conf (5) | |
681 | for more details. | |
cd29a5c8 | 682 | |
52826846 NB |
683 | |
684 | .SH TODO | |
685 | ||
cd29a5c8 | 686 | Finish and document Follow mode. |
52826846 NB |
687 | |
688 | .SH SEE ALSO | |
cd29a5c8 NB |
689 | For information on the various levels of |
690 | RAID, check out: | |
691 | ||
692 | .IP | |
693 | .UR http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/ | |
694 | http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/ | |
695 | .UE | |
696 | .PP | |
697 | for new releases of the RAID driver check out: | |
698 | ||
699 | .IP | |
700 | .UR ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches | |
701 | ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches | |
702 | .UE | |
703 | .PP | |
704 | or | |
705 | .IP | |
706 | .UR http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ | |
707 | http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ | |
708 | .URk | |
709 | .PP | |
56eb10c0 NB |
710 | .BR mdadm.conf (5), |
711 | .BR md (4). | |
712 | .PP | |
52826846 NB |
713 | .IR raidtab (5), |
714 | .IR raid0run (8), | |
715 | .IR raidstop (8), | |
716 | .IR mkraid (8) |