2 .TH MDADM 8 "" v2.0-devel-1
4 mdadm \- manage MD devices
10 .BI mdadm " [mode] <raiddevice> [options] <component-devices>"
13 RAID devices are virtual devices created from two or more
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 include redundancy and so can survive some degree of
20 Linux Software RAID devices are implemented through the md (Multiple
21 Devices) device driver.
23 Currently, Linux supports
37 .B MULTIPATH is not a Software RAID mechanism, but does involve
40 each device is a path to one common physical storage device.
42 .B FAULTY is also no true RAID, and it only involves one device. It
43 provides a layer over a true device that can be used to inject faults.
46 is a program that can be used to create, manage, and monitor
48 such it provides a similar set of functionality to the
51 The key differences between
58 is a single program and not a collection of programs.
61 can perform (almost) all of its functions without having a
62 configuration file and does not use one by default. Also
64 helps with management of the configuration
68 can provide information about your arrays (through Query, Detail, and Examine)
78 configuration file, at all. It has a different configuration file
79 with a different format and an different purpose.
82 mdadm has 7 major modes of operation:
85 Assemble the parts of a previously created
86 array into an active array. Components can be explicitly given
87 or can be searched for.
89 checks that the components
90 do form a bona fide array, and can, on request, fiddle superblock
91 information so as to assemble a faulty array.
95 Build an array without per-device superblocks.
99 Create a new array with per-device superblocks.
101 '''in several step create-add-add-run or it can all happen with one command.
105 This is for doing things to specific components of an array such as
106 adding new spares and removing faulty devices.
110 This mode allows operations on independent devices such as examine MD
111 superblocks, erasing old superblocks and stopping active arrays.
114 .B "Follow or Monitor"
115 Monitor one or more md devices and act on any state changes. This is
116 only meaningful for raid1, 4, 5, 6 or multipath arrays as
117 only these have interesting state. raid0 or linear never have
118 missing, spare, or failed drives, so there is nothing to monitor.
122 Grow (or shrink) an array, or otherwise reshape it in some way.
123 Currently supported growth options including changing the active size
124 of componenet devices in RAID level 1/4/5/6 and changing the number of
125 active devices in RAID1.
129 Available options are:
132 .BR -A ", " --assemble
133 Assemble a pre-existing array.
137 Build a legacy array without superblocks.
145 Examine a device to see
146 (1) if it is an md device and (2) if it is a component of an md
148 Information about what is discovered is presented.
152 Print detail of one or more md devices.
155 .BR -E ", " --examine
156 Print content of md superblock on device(s).
159 .BR -F ", " --follow ", " --monitor
166 Change the size or shape of an active array.
169 .BR -X ", " --examine-bitmap
170 Report information about a bitmap file.
174 Display help message or, after above option, mode specific help
179 Display more detailed help about command line parsing and some commonly
183 .BR -V ", " --version
184 Print version information for mdadm.
187 .BR -v ", " --verbose
188 Be more verbose about what is happening.
192 Be less verbose. This is used with
198 .BR -b ", " --bitmap=
199 Give the name of a bitmap file to use with this array. Can be used
200 with --create (file should not exist) or --assemble (file should
205 Set the Chunksize of the bitmap. Each bit corresponds to that many
206 Kilobytes of storage. Default is 4.
211 Be more forceful about certain operations. See the various modes of
212 the exact meaning of this option in different contexts.
215 .BR -c ", " --config=
216 Specify the config file. Default is
217 .BR /etc/mdadm.conf .
218 If the config file given is
220 then nothing will be read, but
222 will act as though the config file contained exactly
223 .B "DEVICE partitions"
226 to find a list of devices to scan.
229 is given for the config file, then
231 will act as though the config file were empty.
237 for missing information.
238 In general, this option gives
240 permission to get any missing information, like component devices,
241 array devices, array identities, and alert destination from the
243 .BR /etc/mdadm.conf .
244 One exception is MISC mode when using
250 says to get a list of array devices from
254 .B -e ", " --metadata=
255 Declare the style of superblock (raid metadata) to be used. The
256 default is 0.90 for --create, and to guess for other operations.
260 .IP "0, 0.90, default"
261 Use the original 0.90 format superblock. This format limits arrays to
262 28 componenet devices and limits component devices of levels 1 and
263 greater to 2 terabytes.
264 .IP "1, 1.0, 1.1, 1.2"
265 Use the new version-1 format superblock. This has few restrictions.
266 The different subversion store the superblock at different locations
267 on the device, either at the end (for 1.0), at the start (for 1.1) or
268 4K from the start (for 1.2).
271 .SH For create or build:
275 Specify chunk size of kibibytes. The default is 64.
279 Specify rounding factor for linear array (==chunk size)
283 Set raid level. When used with
285 options are: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4,
286 raid5, 5, raid6, 6, multipath, mp, fautly. Obviously some of these are synonymous.
290 only linear, raid0, 0, stripe are valid.
293 .BR -p ", " --parity=
294 Set raid5 parity algorithm. Options are:
299 la, ra, ls, rs. The default is left-symmetric.
301 This option is also used to set the failure mode for
319 Each mode can be followed by a number which is used as a period
320 between fault generation. Without a number, the fault is generated
321 once on the first relevant request. With a number, the fault will be
322 generated after that many request, and will continue to be generated
323 every time the period elapses.
325 Multiple failure modes can be current simultaneously by using the
326 "--grow" option to set subsequent failure modes.
328 "clear" or "none" will remove any pending or periodic failure modes,
329 and "flush" will clear any persistant faults.
331 To set the parity with "--grow", the level of the array ("faulty")
332 must be specified before the fault mode is specified.
339 .BR -b ", " --bitmap=
340 Specify a file to store a write-intent bitmap in. The file should not
341 exist unless --force is also given. The same file should be provided
342 when assembling the array.
346 Specifty the chunksize for the bitmap.
349 .BR -n ", " --raid-devices=
350 Specify the number of active devices in the array. This, plus the
351 number of spare devices (see below) must equal the number of
353 (including "\fBmissing\fP" devices)
354 that are listed on the command line for
356 Setting a value of 1 is probably
357 a mistake and so requires that
359 be specified first. A value of 1 will then be allowed for linear,
360 multipath, raid0 and raid1. It is never allowed for raid4 or raid5.
362 This number can only be changed using
364 for RAID1 arrays, and only on kernels which provide necessary support.
367 .BR -x ", " --spare-devices=
368 Specify the number of spare (eXtra) devices in the initial array.
369 Spares can also be added
370 and removed later. The number of component devices listed
371 on the command line must equal the number of raid devices plus the
372 number of spare devices.
377 Amount (in Kibibytes) of space to use from each drive in RAID1/4/5/6.
378 This must be a multiple of the chunk size, and must leave about 128Kb
379 of space at the end of the drive for the RAID superblock.
380 If this is not specified
381 (as it normally is not) the smallest drive (or partition) sets the
382 size, though if there is a variance among the drives of greater than 1%, a warning is
385 This value can be set with
387 for RAID level 1/4/5/6. If the array was created with a size smaller
388 than the currently active drives, the extra space can be accessed
396 that the array pre-existed and is known to be clean. This is only
397 really useful for Building RAID1 array. Only use this if you really
398 know what you are doing. This is currently only supported for --build.
404 run the array, even if some of the components
405 appear to be active in another array or filesystem. Normally
407 will ask for confirmation before including such components in an
408 array. This option causes that question to be suppressed.
414 accept the geometry and layout specified without question. Normally
416 will not allow creation of an array with only one device, and will try
417 to create a raid5 array with one missing drive (as this makes the
418 initial resync work faster). With
421 will not try to be so clever.
424 .BR -a ", " "--auto{=no,yes,md,mdp,part,p}{NN}"
425 Instruct mdadm to create the device file if needed, possibly allocating
426 an unused minor number. "md" causes a non-partitionable array
427 to be used. "mdp", "part" or "p" causes a partitionable array (2.6 and
428 later) to be used. "yes" requires the named md device to have a
429 'standard' format, and the type and minor number will be determined
430 from this. See DEVICE NAMES below.
432 The argumentment can also come immediately after
435 For partitionable arrays,
437 will create the device file for the whole array and for the first 4
438 partitions. A different number of partitions can be specified at the
439 end of this option (e.g.
441 If the device name ends with a digit, the partition names add a'p',
442 and a number, e.g. "/dev/home1p3". If there is no
443 trailing digit, then the partition names just have a number added,
444 e.g. "/dev/scratch3".
446 If the md device name is in a 'standard' format as described in DEVICE
447 NAMES, then it will be created, if necessary, with the appropriate
448 number based on that name. If the device name is not in one of these
449 formats, then a unused minor number will be allocted. The minor
450 number will be considered unused if there is no active array for that
451 number, and there is no entry in /dev for that number and with a
458 uuid of array to assemble. Devices which don't have this uuid are
462 .BR -m ", " --super-minor=
463 Minor number of device that array was created for. Devices which
464 don't have this minor number are excluded. If you create an array as
465 /dev/md1, then all superblocks will contain the minor number 1, even if
466 the array is later assembled as /dev/md2.
468 Giving the literal word "dev" for
472 to use the minor number of the md device that is being assembled.
476 will look for super blocks with a minor number of 0.
480 Assemble the array even if some superblocks appear out-of-date
484 Attempt to start the array even if fewer drives were given than are
485 needed for a full array. Normally if not all drives are found and
487 is not used, then the array will be assembled but not started.
490 an attempt will be made to start it anyway.
493 .BR -a ", " "--auto{=no,yes,md,mdp,part}"
494 See this option under Create and Build options.
497 .BR -b ", " --bitmap=
498 Specify the bitmap file that was given when the array was created.
501 .BR -U ", " --update=
502 Update the superblock on each device while assembling the array. The
503 argument given to this flag can be one of
512 option will adjust the superblock of an array what was created on a Sparc
513 machine running a patched 2.2 Linux kernel. This kernel got the
514 alignment of part of the superblock wrong. You can use the
515 .B "--examine --sparc2.2"
518 to see what effect this would have.
522 option will update the
524 field on each superblock to match the minor number of the array being
525 assembled. This is not needed on 2.6 and later kernels as they make
526 this adjustment automatically.
530 option will cause the array to be marked
532 meaning that any redundancy in the array (e.g. parity for raid5,
533 copies for raid1) may be incorrect. This will cause the raid system
534 to perform a "resync" pass to make sure that all redundant information
539 option will correct the summaries in the superblock. That is the
540 counts of total, working, active, failed, and spare devices.
547 hotadd listed devices.
551 remove listed devices. They must not be active. i.e. they should
552 be failed or spare devices.
556 mark listed devices as faulty.
562 .SH For Examine mode:
566 In an array was created on a 2.2 Linux kernel patched with RAID
567 support, the superblock will have been created incorrectly, or at
568 least incompatibly with 2.4 and later kernels. Using the
572 will fix the superblock before displaying it. If this appears to do
573 the right thing, then the array can be successfully assembled using
574 .BR "--assemble --update=sparc2.2" .
580 start a partially built array.
584 deactivate array, releasing all resources.
587 .BR -o ", " --readonly
588 mark array as readonly.
591 .BR -w ", " --readwrite
592 mark array as readwrite.
596 If the device contains a valid md superblock, the block is
597 over-written with zeros. With
599 the block where the superblock would be is over-written even if it
600 doesn't appear to be valid.
608 is set to reflect the status of the device.
610 .SH For Monitor mode:
613 Give a mail address to send alerts to.
616 .BR -p ", " --program ", " --alert
617 Give a program to be run whenever an event is detected.
621 Give a delay in seconds.
623 polls the md arrays and then waits this many seconds before polling
624 again. The default is 60 seconds.
627 .BR -f ", " --daemonise
630 to run as a background daemon if it decides to monitor anything. This
631 causes it to fork and run in the child, and to disconnect form the
632 terminal. The process id of the child is written to stdout.
635 which will only continue monitoring if a mail address or alert program
636 is found in the config file.
639 .BR -i ", " --pid-file
642 is running in daemon mode, write the pid of the daemon process to
643 the specified file, instead of printing it on standard output.
646 .BR -1 ", " --oneshot
647 Check arrays only once. This will generate
649 events and more significantly
653 .B " mdadm --monitor --scan -1"
655 from a cron script will ensure regular notification of any degraded arrays.
661 alert for every array found at startup. This alert gets mailed and
662 passed to the alert program. This can be used for testing that alert
663 message to get through successfully.
670 .I md-device options-and-component-devices...
673 .B mdadm --assemble --scan
674 .I md-devices-and-options...
677 .B mdadm --assemble --scan
681 This usage assembles one or more raid arrays from pre-existing components.
682 For each array, mdadm needs to know the md device, the identity of the
683 array, and a number of component-devices. These can be found in a number of ways.
685 In the first usage example (without the
687 the first device given is the md device.
688 In the second usage example, all devices listed are treated as md
689 devices and assembly is attempted.
690 In the third (where no devices are listed) all md devices that are
691 listed in the configuration file are assembled.
693 If precisely one device is listed, but
699 was given and identify information is extracted from the configuration file.
701 The identity can be given with the
705 option, can be found in the config file, or will be taken from the
706 super block on the first component-device listed on the command line.
708 Devices can be given on the
710 command line or in the config file. Only devices which have an md
711 superblock which contains the right identity will be considered for
714 The config file is only used if explicitly named with
716 or requested with (a possibly implicit)
724 is not given, then the config file will only be used to find the
725 identity of md arrays.
727 Normally the array will be started after it is assembled. However if
729 is not given and insufficient drives were listed to start a complete
730 (non-degraded) array, then the array is not started (to guard against
731 usage errors). To insist that the array be started in this case (as
732 may work for RAID1, 4, 5 or 6), give the
738 option is given, either on the command line (--auto) or in the
739 configuration file (e.g. auto=part), then
741 will create the md device if necessary or will re-create it if it
742 doesn't look usable as it is.
744 This can be useful for handling partitioned devices (which don't have
745 a stable device number - it can change after a reboot) and when using
746 "udev" to manage your
748 tree (udev cannot handle md devices because of the unusual device
749 initialisation conventions).
751 If the option to "auto" is "mdp" or "part" or (on the command line
752 only) "p", then mdadm will create a partitionable array, using the
753 first free one that is not inuse, and does not already have an entry
754 in /dev (apart from numeric /dev/md* entries).
756 If the option to "auto" is "yes" or "md" or (on the command line)
757 nothing, then mdadm will create a traditional, non-partitionable md
760 It is expected that the "auto" functionality will be used to create
761 device entries with meaningful names such as "/dev/md/home" or
762 "/dev/md/root", rather than names based on the numerical array number.
764 When using this option to create a partitionable array, the device
765 files for the first 4 partitions are also created. If a different
766 number is required it can be simply appended to the auto option.
767 e.g. "auto=part8". Partition names are created by appending a digit
768 string to the device name, with an intervening "_p" if the device name
773 option is also available in Build and Create modes. As those modes do
774 not use a config file, the "auto=" config option does not apply to
785 .BI --raid-devices= Z
789 This usage is similar to
791 The difference is that it creates a legacy array without a superblock. With
792 these arrays there is no difference between initially creating the array and
793 subsequently assembling the array, except that hopefully there is useful
794 data there in the second case.
796 The level may only be 0, raid0, or linear. All devices must be listed
797 and the array will be started once complete.
808 .BI --raid-devices= Z
812 This usage will initialise a new md array, associate some devices with
813 it, and activate the array.
817 option is given (as described in more detail in the section on
818 Assemble mode), then the md device will be created with a suitable
819 device number if necessary.
821 As devices are added, they are checked to see if they contain raid
822 superblocks or filesystems. They are also checked to see if the variance in
823 device size exceeds 1%.
825 If any discrepancy is found, the array will not automatically be run, though
828 can override this caution.
830 To create a "degraded" array in which some devices are missing, simply
831 give the word "\fBmissing\fP"
832 in place of a device name. This will cause
834 to leave the corresponding slot in the array empty.
835 For a RAID4 or RAID5 array at most one slot can be
836 "\fBmissing\fP"; for a RAID6 array at most two slots.
837 For a RAID1 array, only one real device needs to be given. All of the
841 When creating a RAID5 array,
843 will automatically create a degraded array with an extra spare drive.
844 This is because building the spare into a degraded array is in general faster than resyncing
845 the parity on a non-degraded, but not clean, array. This feature can
846 be over-ridden with the
852 '''option is given, it is not necessary to list any component-devices in this command.
853 '''They can be added later, before a
857 '''is given, the apparent size of the smallest drive given is used.
859 The General Management options that are valid with --create are:
862 insist on running the array even if some devices look like they might
867 start the array readonly - not supported yet.
874 .I options... devices...
877 This usage will allow individual devices in an array to be failed,
878 removed or added. It is possible to perform multiple operations with
879 on command. For example:
881 .B " mdadm /dev/md0 -f /dev/hda1 -r /dev/hda1 -a /dev/hda1"
887 and will then remove it from the array and finally add it back
888 in as a spare. However only one md array can be affected by a single
899 MISC mode includes a number of distinct operations that
900 operate on distinct devices. The operations are:
903 The device is examined to see if it is
904 (1) an active md array, or
905 (2) a component of an md array.
906 The information discovered is reported.
910 The device should be an active md device.
912 will display a detailed description of the array.
916 will cause the output to be less detailed and the format to be
917 suitable for inclusion in
918 .BR /etc/mdadm.conf .
921 will normally be 0 unless
923 failed to get useful information about the device(s). However if the
925 option is given, then the exit status will be:
929 The array is functioning normally.
932 The array has at least one failed device.
935 The array has multiple failed devices and hence is unusable (raid4 or
939 There was an error while trying to get information about the device.
944 The device should be a component of an md array.
946 will read the md superblock of the device and display the contents.
951 then multiple devices that are components of the one array
952 are grouped together and reported in a single entry suitable
954 .BR /etc/mdadm.conf .
958 without listing any devices will cause all devices listed in the
959 config file to be examined.
963 The devices should be active md arrays which will be deactivated, as
964 long as they are not currently in use.
968 This will fully activate a partially assembled md array.
972 This will mark an active array as read-only, providing that it is
973 not currently being used.
979 array back to being read/write.
983 For all operations except
986 will cause the operation to be applied to all arrays listed in
991 causes all devices listed in the config file to be examined.
999 .I options... devices...
1004 to periodically poll a number of md arrays and to report on any events
1007 will never exit once it decides that there are arrays to be checked,
1008 so it should normally be run in the background.
1010 As well as reporting events,
1012 may move a spare drive from one array to another if they are in the
1015 and if the destination array has a failed drive but not spares.
1017 If any devices are listed on the command line,
1019 will only monitor those devices. Otherwise all arrays listed in the
1020 configuration file will be monitored. Further, if
1022 is given, then any other md devices that appear in
1024 will also be monitored.
1026 The result of monitoring the arrays is the generation of events.
1027 These events are passed to a separate program (if specified) and may
1028 be mailed to a given E-mail address.
1030 When passing event to program, the program is run once for each event
1031 and is given 2 or 3 command-line arguements. The first is the
1032 name of the event (see below). The second is the name of the
1033 md device which is affected, and the third is the name of a related
1034 device if relevant, such as a component device that has failed.
1038 is given, then a program or an E-mail address must be specified on the
1039 command line or in the config file. If neither are available, then
1041 will not monitor anything.
1045 will continue monitoring as long as something was found to monitor. If
1046 no program or email is given, then each event is reported to
1049 The different events are:
1053 .B DeviceDisappeared
1054 An md array which previously was configured appears to no longer be
1059 An md array started reconstruction.
1065 is 20, 40, 60, or 80, this indicates that rebuild has passed that many
1066 percentage of the total.
1070 An md array that was rebuilding, isn't any more, either because it
1071 finished normally or was aborted.
1075 An active component device of an array has been marked as faulty.
1079 A spare component device which was being rebuilt to replace a faulty
1084 A spare component device which was being rebuilt to replace a faulty
1085 device as been successfully rebuild and has been made active.
1089 A new md array has been detected in the
1095 A newly noticed array appears to be degraded. This message is not
1098 notices a drive failure which causes degradation, but only when
1100 notices that an array is degraded when it first sees the array.
1104 A spare drive has been moved from one array in a
1106 to another to allow a failed drive to be replaced.
1110 An array was found at startup, and the
1121 cause Email to be sent. All events cause the program to be run.
1122 The program is run with two or three arguments, they being the event
1123 name, the array device and possibly a second device.
1125 Each event has an associated array device (e.g.
1127 and possibly a second device. For
1132 the second device is the relevant component device.
1135 the second device is the array that the spare was moved from.
1139 to move spares from one array to another, the different arrays need to
1140 be labelled with the same
1142 in the configuration file. The
1144 name can be any string. It is only necessary that different spare
1145 groups use different names.
1149 detects that an array which is in a spare group has fewer active
1150 devices than necessary for the complete array, and has no spare
1151 devices, it will look for another array in the same spare group that
1152 has a full complement of working drive and a spare. It will then
1153 attempt to remove the spare from the second drive and add it to the
1155 If the removal succeeds but the adding fails, then it is added back to
1159 The GROW mode is used for changing the size or shape of an active
1161 For this to work, the kernel must support the necessary change.
1162 Various types of growth may be added during 2.6 development, possibly
1163 including restructuring a raid5 array to have more active devices.
1165 Currently the only support available is to change the "size" attribute
1166 for arrays with redundancy, and the raid-disks attribute of RAID1
1169 Normally when an array is build the "size" it taken from the smallest
1170 of the drives. If all the small drives in an arrays are, one at a
1171 time, removed and replaced with larger drives, then you could have an
1172 array of large drives with only a small amount used. In this
1173 situation, changing the "size" with "GROW" mode will allow the extra
1174 space to start being used. If the size is increased in this way, a
1175 "resync" process will start to make sure the new parts of the array
1178 Note that when an array changes size, any filesystem that may be
1179 stored in the array will not automatically grow to use the space. The
1180 filesystem will need to be explicitly told to use the extra space.
1182 A RAID1 array can work with any number of devices from 1 upwards
1183 (though 1 is not very useful). There may be times which you want to
1184 increase or decrease the number of active devices. Note that this is
1185 different to hot-add or hot-remove which changes the number of
1188 When reducing the number of devices in a RAID1 array, the slots which
1189 are to be removed from the array must already be vacant. That is, the
1190 devices that which were in those slots must be failed and removed.
1192 When the number of devices is increased, any hot spares that are
1193 present may be activated immediately.
1197 .B " mdadm --query /dev/name-of-device"
1199 This will find out if a given device is a raid array, or is part of
1200 one, and will provide brief information about the device.
1202 .B " mdadm --assemble --scan"
1204 This will assemble and start all arrays listed in the standard confile
1205 file. This command will typically go in a system startup file.
1207 .B " mdadm --stop --scan"
1209 This will shut down all array that can be shut down (i.e. are not
1210 currently in use). This will typically go in a system shutdown script.
1212 .B " mdadm --follow --scan --delay=120"
1214 If (and only if) there is an Email address or program given in the
1215 standard config file, then
1216 monitor the status of all arrays listed in that file by
1217 polling them ever 2 minutes.
1219 .B " mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/hd[ac]1"
1221 Create /dev/md0 as a RAID1 array consisting of /dev/hda1 and /dev/hdc1.
1224 .B " echo 'DEVICE /dev/hd*[0-9] /dev/sd*[0-9]' > mdadm.conf"
1226 .B " mdadm --detail --scan >> mdadm.conf"
1228 This will create a prototype config file that describes currently
1229 active arrays that are known to be made from partitions of IDE or SCSI drives.
1230 This file should be reviewed before being used as it may
1231 contain unwanted detail.
1233 .B " echo 'DEVICE /dev/hd[a-z] /dev/sd*[a-z]' > mdadm.conf"
1235 .B " mdadm --examine --scan --config=mdadm.conf >> mdadm.conf"
1237 This will find what arrays could be assembled from existign IDE and
1238 SCSI whole drives (not partitions) and store the information is the
1239 format of a config file.
1240 This file is very likely to contain unwanted detail, particularly
1243 entries. It should be reviewed and edited before being used as an
1246 .B " mdadm --examine --brief --scan --config=partitions"
1248 .B " mdadm -Ebsc partitions"
1250 Create a list of devices by reading
1251 .BR /proc/partitions ,
1252 scan these for RAID superblocks, and printout a brief listing of all
1255 .B " mdadm -Ac partitions -m 0 /dev/md0"
1257 Scan all partitions and devices listed in
1258 .BR /proc/partitions
1261 out of all such devices with a RAID superblock with a minor number of 0.
1263 .B " mdadm --monitor --scan --daemonise > /var/run/mdadm"
1265 If config file contains a mail address or alert program, run mdadm in
1266 the background in monitor mode monitoring all md devices. Also write
1267 pid of mdadm daemon to
1268 .BR /var/run/mdadm .
1270 .B " mdadm --create --help"
1272 Providew help about the Create mode.
1274 .B " mdadm --config --help"
1276 Provide help about the format of the config file.
1280 Provide general help.
1291 lists all active md devices with information about them.
1293 uses this to find arrays when
1295 is given in Misc mode, and to monitor array reconstruction
1301 The config file lists which devices may be scanned to see if
1302 they contain MD super block, and gives identifying information
1303 (e.g. UUID) about known MD arrays. See
1309 While entries in the /dev directory can have any format you like,
1311 has an understanding of 'standard' formats which it uses to guide its
1312 behaviour when creating device files via the
1316 The standard names for non-partitioned arrays (the only sort of md
1317 array available in 2.4 and earlier) either of
1323 where NN is a number.
1324 The standard names for partitionable arrays (as available from 2.6
1331 Partition numbers should be indicated by added "pMM" to these, thus "/dev/md/d1p2".
1335 was previously known as
1339 For information on the various levels of
1343 .UR http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/
1344 http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/
1347 for new releases of the RAID driver check out:
1350 .UR ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches
1351 ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches
1356 .UR http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/
1357 http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/
projects / thirdparty / mdadm.git / blob