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