X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fmdadm.git;a=blobdiff_plain;f=mdadm.8;h=a5d8e0dce018fd612f1a02e43e9eb5ba6867b16a;hp=65684699e66c24a8d080521de1b6cc43d8c7b9a4;hb=a322f70c41a1c381e19b1913b8ad2a8b77078800;hpb=b3f1c093b77428e5746a563da1526da156011065 diff --git a/mdadm.8 b/mdadm.8 index 65684699..a5d8e0dc 100644 --- a/mdadm.8 +++ b/mdadm.8 @@ -1,15 +1,15 @@ .\" -*- nroff -*- -''' Copyright Neil Brown and others. -''' This program is free software; you can redistribute it and/or modify -''' it under the terms of the GNU General Public License as published by -''' the Free Software Foundation; either version 2 of the License, or -''' (at your option) any later version. -''' See file COPYING in distribution for details. -.TH MDADM 8 "" v2.6.1 +.\" Copyright Neil Brown and others. +.\" This program is free software; you can redistribute it and/or modify +.\" it under the terms of the GNU General Public License as published by +.\" the Free Software Foundation; either version 2 of the License, or +.\" (at your option) any later version. +.\" See file COPYING in distribution for details. +.TH MDADM 8 "" v2.6.5 .SH NAME mdadm \- manage MD devices .I aka -Linux Software Raid. +Linux Software RAID .SH SYNOPSIS @@ -43,55 +43,54 @@ and .B MULTIPATH is not a Software RAID mechanism, but does involve -multiple devices. For -.B MULTIPATH +multiple devices: each device is a path to one common physical storage device. .B FAULTY is also not true RAID, and it only involves one device. It provides a layer over a true device that can be used to inject faults. -'''.B mdadm -'''is a program that can be used to create, manage, and monitor -'''MD devices. As -'''such it provides a similar set of functionality to the -'''.B raidtools -'''packages. -'''The key differences between -'''.B mdadm -'''and -'''.B raidtools -'''are: -'''.IP \(bu 4 -'''.B mdadm -'''is a single program and not a collection of programs. -'''.IP \(bu 4 -'''.B mdadm -'''can perform (almost) all of its functions without having a -'''configuration file and does not use one by default. Also -'''.B mdadm -'''helps with management of the configuration -'''file. -'''.IP \(bu 4 -'''.B mdadm -'''can provide information about your arrays (through Query, Detail, and Examine) -'''that -'''.B raidtools -'''cannot. -'''.P -'''.I mdadm -'''does not use -'''.IR /etc/raidtab , -'''the -'''.B raidtools -'''configuration file, at all. It has a different configuration file -'''with a different format and a different purpose. +.\".B mdadm +.\"is a program that can be used to create, manage, and monitor +.\"MD devices. As +.\"such it provides a similar set of functionality to the +.\".B raidtools +.\"packages. +.\"The key differences between +.\".B mdadm +.\"and +.\".B raidtools +.\"are: +.\".IP \(bu 4 +.\".B mdadm +.\"is a single program and not a collection of programs. +.\".IP \(bu 4 +.\".B mdadm +.\"can perform (almost) all of its functions without having a +.\"configuration file and does not use one by default. Also +.\".B mdadm +.\"helps with management of the configuration +.\"file. +.\".IP \(bu 4 +.\".B mdadm +.\"can provide information about your arrays (through Query, Detail, and Examine) +.\"that +.\".B raidtools +.\"cannot. +.\".P +.\".I mdadm +.\"does not use +.\".IR /etc/raidtab , +.\"the +.\".B raidtools +.\"configuration file, at all. It has a different configuration file +.\"with a different format and a different purpose. .SH MODES mdadm has several major modes of operation: .TP .B Assemble -Assemble the parts of a previously created +Assemble the components of a previously created array into an active array. Components can be explicitly given or can be searched for. .B mdadm @@ -106,7 +105,7 @@ sorts of arrays, .I mdadm cannot differentiate between initial creation and subsequent assembly of an array. It also cannot perform any checks that appropriate -devices have been requested. Because of this, the +components have been requested. Because of this, the .B Build mode should only be used together with a complete understanding of what you are doing. @@ -114,13 +113,13 @@ what you are doing. .TP .B Create Create a new array with per-device superblocks. -'''It can progress -'''in several step create-add-add-run or it can all happen with one command. +.\"It can progress +.\"in several step create-add-add-run or it can all happen with one command. .TP .B "Follow or Monitor" Monitor one or more md devices and act on any state changes. This is -only meaningful for raid1, 4, 5, 6, 10 or multipath arrays as +only meaningful for raid1, 4, 5, 6, 10 or multipath arrays, as only these have interesting state. raid0 or linear never have missing, spare, or failed drives, so there is nothing to monitor. @@ -128,8 +127,8 @@ missing, spare, or failed drives, so there is nothing to monitor. .B "Grow" Grow (or shrink) an array, or otherwise reshape it in some way. Currently supported growth options including changing the active size -of component devices in RAID level 1/4/5/6 and changing the number of -active devices in RAID1/5/6. +of component devices and changing the number of active devices in RAID +levels 1/4/5/6, as well as adding or removing a write-intent bitmap. .TP .B "Incremental Assembly" @@ -151,45 +150,64 @@ adding new spares and removing faulty devices. This is an 'everything else' mode that supports operations on active arrays, operations on component devices such as erasing old superblocks, and information gathering operations. -'''This mode allows operations on independent devices such as examine MD -'''superblocks, erasing old superblocks and stopping active arrays. +.\"This mode allows operations on independent devices such as examine MD +.\"superblocks, erasing old superblocks and stopping active arrays. +.TP +.B Auto-detect +This mode does not act on a specific device or array, but rather it +requests the Linux Kernel to activate any auto-detected arrays. .SH OPTIONS .SH Options for selecting a mode are: .TP -.BR -A ", " --assemble +.BR \-A ", " \-\-assemble Assemble a pre-existing array. .TP -.BR -B ", " --build +.BR \-B ", " \-\-build Build a legacy array without superblocks. .TP -.BR -C ", " --create +.BR \-C ", " \-\-create Create a new array. .TP -.BR -F ", " --follow ", " --monitor +.BR \-F ", " \-\-follow ", " \-\-monitor Select .B Monitor mode. .TP -.BR -G ", " --grow +.BR \-G ", " \-\-grow Change the size or shape of an active array. .TP -.BE -I ", " --incremental +.BR \-I ", " \-\-incremental Add a single device into an appropriate array, and possibly start the array. +.TP +.B \-\-auto-detect +Request that the kernel starts any auto-detected arrays. This can only +work if +.I md +is compiled into the kernel \(em not if it is a module. +Arrays can be auto-detected by the kernel if all the components are in +primary MS-DOS partitions with partition type +.BR FD . +In-kernel autodetect is not recommended for new installations. Using +.I mdadm +to detect and assemble arrays \(em possibly in an +.I initrd +\(em is substantially more flexible and should be preferred. + .P If a device is given before any options, or if the first option is -.BR --add , -.BR --fail , +.BR \-\-add , +.BR \-\-fail , or -.BR --remove , +.BR \-\-remove , then the MANAGE mode is assume. Anything other than these will cause the .B Misc @@ -198,59 +216,59 @@ mode to be assumed. .SH Options that are not mode-specific are: .TP -.BR -h ", " --help +.BR \-h ", " \-\-help Display general help message or, after one of the above options, a -mode specific help message. +mode-specific help message. .TP -.B --help-options +.B \-\-help\-options Display more detailed help about command line parsing and some commonly used options. .TP -.BR -V ", " --version +.BR \-V ", " \-\-version Print version information for mdadm. .TP -.BR -v ", " --verbose +.BR \-v ", " \-\-verbose Be more verbose about what is happening. This can be used twice to be extra-verbose. The extra verbosity currently only affects -.B --detail --scan +.B \-\-detail \-\-scan and -.BR "--examine --scan" . +.BR "\-\-examine \-\-scan" . .TP -.BR -q ", " --quiet +.BR \-q ", " \-\-quiet Avoid printing purely informative messages. With this, .B mdadm will be silent unless there is something really important to report. .TP -.BR -b ", " --brief +.BR \-b ", " \-\-brief Be less verbose. This is used with -.B --detail +.B \-\-detail and -.BR --examine . +.BR \-\-examine . Using -.B --brief +.B \-\-brief with -.B --verbose +.B \-\-verbose gives an intermediate level of verbosity. .TP -.BR -f ", " --force -Be more forceful about certain operations. See the various modes of +.BR \-f ", " \-\-force +Be more forceful about certain operations. See the various modes for the exact meaning of this option in different contexts. .TP -.BR -c ", " --config= +.BR \-c ", " \-\-config= Specify the config file. Default is to use .BR /etc/mdadm.conf , -or if that is missing, then +or if that is missing then .BR /etc/mdadm/mdadm.conf . If the config file given is -.B partitions +.B "partitions" then nothing will be read, but .I mdadm will act as though the config file contained exactly @@ -259,35 +277,36 @@ and will read .B /proc/partitions to find a list of devices to scan. If the word -.B none +.B "none" is given for the config file, then .I mdadm will act as though the config file were empty. .TP -.BR -s ", " --scan -scan config file or +.BR \-s ", " \-\-scan +Scan config file or .B /proc/mdstat for missing information. In general, this option gives .B mdadm -permission to get any missing information, like component devices, -array devices, array identities, and alert destination from the -configuration file: -.BR /etc/mdadm.conf . -One exception is MISC mode when using -.B --detail +permission to get any missing information (like component devices, +array devices, array identities, and alert destination) from the +configuration file (see previous option); +one exception is MISC mode when using +.B \-\-detail or -.B --stop +.B \-\-stop, in which case -.B --scan +.B \-\-scan says to get a list of array devices from .BR /proc/mdstat . .TP -.B -e ", " --metadata= +.B \-e ", " \-\-metadata= Declare the style of superblock (raid metadata) to be used. The -default is 0.90 for --create, and to guess for other operations. +default is 0.90 for +.BR \-\-create , +and to guess for other operations. The default can be overridden by setting the .B metadata value for the @@ -299,26 +318,26 @@ Options are: .RS .IP "0, 0.90, default" Use the original 0.90 format superblock. This format limits arrays to -28 componenet devices and limits component devices of levels 1 and +28 component devices and limits component devices of levels 1 and greater to 2 terabytes. .IP "1, 1.0, 1.1, 1.2" Use the new version-1 format superblock. This has few restrictions. -The different subversion store the superblock at different locations +The different sub-versions store the superblock at different locations on the device, either at the end (for 1.0), at the start (for 1.1) or 4K from the start (for 1.2). .RE .TP -.B --homehost= +.B \-\-homehost= This will override any .B HOMEHOST -setting in the config file and provides the identify of the host which +setting in the config file and provides the identity of the host which should be considered the home for any arrays. When creating an array, the .B homehost will be recorded in the superblock. For version-1 superblocks, it will -be prefixed to the array name. For version-0.90 superblocks part of +be prefixed to the array name. For version-0.90 superblocks, part of the SHA1 hash of the hostname will be stored in the later half of the UUID. @@ -331,26 +350,26 @@ will be assembled. .SH For create, build, or grow: .TP -.BR -n ", " --raid-devices= +.BR \-n ", " \-\-raid\-devices= Specify the number of active devices in the array. This, plus the number of spare devices (see below) must equal the number of .I component-devices (including "\fBmissing\fP" devices) that are listed on the command line for -.BR --create . +.BR \-\-create . Setting a value of 1 is probably a mistake and so requires that -.B --force +.B \-\-force be specified first. A value of 1 will then be allowed for linear, multipath, raid0 and raid1. It is never allowed for raid4 or raid5. .br This number can only be changed using -.B --grow +.B \-\-grow for RAID1, RAID5 and RAID6 arrays, and only on kernels which provide necessary support. .TP -.BR -x ", " --spare-devices= +.BR \-x ", " \-\-spare\-devices= Specify the number of spare (eXtra) devices in the initial array. Spares can also be added and removed later. The number of component devices listed @@ -359,8 +378,8 @@ number of spare devices. .TP -.BR -z ", " --size= -Amount (in Kibibytes) of space to use from each drive in RAID1/4/5/6. +.BR \-z ", " \-\-size= +Amount (in Kibibytes) of space to use from each drive in RAID level 1/4/5/6. This must be a multiple of the chunk size, and must leave about 128Kb of space at the end of the drive for the RAID superblock. If this is not specified @@ -369,101 +388,99 @@ size, though if there is a variance among the drives of greater than 1%, a warni issued. This value can be set with -.B --grow +.B \-\-grow for RAID level 1/4/5/6. If the array was created with a size smaller than the currently active drives, the extra space can be accessed using -.BR --grow . +.BR \-\-grow . The size can be given as .B max which means to choose the largest size that fits on all current drives. .TP -.BR -c ", " --chunk= +.BR \-c ", " \-\-chunk= Specify chunk size of kibibytes. The default is 64. .TP -.BR --rounding= +.BR \-\-rounding= Specify rounding factor for linear array (==chunk size) .TP -.BR -l ", " --level= +.BR \-l ", " \-\-level= Set raid level. When used with -.IR --create , +.BR \-\-create , options are: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4, raid5, 5, raid6, 6, raid10, 10, multipath, mp, faulty. Obviously some of these are synonymous. When used with -.IR --build , +.BR \-\-build , only linear, stripe, raid0, 0, raid1, multipath, mp, and faulty are valid. Not yet supported with -.IR --grow . +.BR \-\-grow . .TP -.BR -p ", " --layout= +.BR \-p ", " \-\-layout= This option configures the fine details of data layout for raid5, and raid10 arrays, and controls the failure modes for .IR faulty . The layout of the raid5 parity block can be one of -left-asymmetric, -left-symmetric, -right-asymmetric, -right-symmetric, -la, ra, ls, rs. The default is left-symmetric. - -When setting the failure mode for -.I faulty +.BR left\-asymmetric , +.BR left\-symmetric , +.BR right\-asymmetric , +.BR right\-symmetric , +.BR la ", " ra ", " ls ", " rs . +The default is +.BR left\-symmetric . + +When setting the failure mode for level +.I faulty, the options are: -write-transient, -wt, -read-transient, -rt, -write-persistent, -wp, -read-persistent, -rp, -write-all, -read-fixable, -rf, -clear, -flush, -none. - -Each mode can be followed by a number which is used as a period +.BR write\-transient ", " wt , +.BR read\-transient ", " rt , +.BR write\-persistent ", " wp , +.BR read\-persistent ", " rp , +.BR write\-all , +.BR read\-fixable ", " rf , +.BR clear ", " flush ", " none . + +Each failure mode can be followed by a number, which is used as a period between fault generation. Without a number, the fault is generated once on the first relevant request. With a number, the fault will be -generated after that many request, and will continue to be generated +generated after that many requests, and will continue to be generated every time the period elapses. Multiple failure modes can be current simultaneously by using the -"--grow" option to set subsequent failure modes. +.B \-\-grow +option to set subsequent failure modes. "clear" or "none" will remove any pending or periodic failure modes, and "flush" will clear any persistent faults. -To set the parity with "--grow", the level of the array ("faulty") +To set the parity with +.BR \-\-grow , +the level of the array ("faulty") must be specified before the fault mode is specified. -Finally, the layout options for RAID10 are one of 'n', 'o' or 'p' followed -by a small number. The default is 'n2'. +Finally, the layout options for RAID10 are one of 'n', 'o' or 'f' followed +by a small number. The default is 'n2'. The supported options are: -.I n +.I 'n' signals 'near' copies. Multiple copies of one data block are at similar offsets in different devices. -.I o +.I 'o' signals 'offset' copies. Rather than the chunks being duplicated within a stripe, whole stripes are duplicated but are rotated by one device so duplicate blocks are on different devices. Thus subsequent copies of a block are in the next drive, and are one chunk further down. -.I f +.I 'f' signals 'far' copies -(multiple copies have very different offsets). See md(4) for more -detail about 'near' and 'far'. +(multiple copies have very different offsets). +See md(4) for more detail about 'near' and 'far'. The number is the number of copies of each datablock. 2 is normal, 3 can be useful. This number can be at most equal to the number of @@ -472,21 +489,25 @@ number (e.g. it is perfectly legal to have an 'n2' layout for an array with an odd number of devices). .TP -.BR --parity= -same as --layout (thus explaining the p of -.IR -p ). +.BR \-\-parity= +same as +.B \-\-layout +(thus explaining the p of +.BR \-p ). .TP -.BR -b ", " --bitmap= +.BR \-b ", " \-\-bitmap= Specify a file to store a write-intent bitmap in. The file should not -exist unless --force is also given. The same file should be provided +exist unless +.B \-\-force +is also given. The same file should be provided when assembling the array. If the word -.B internal +.B "internal" is given, then the bitmap is stored with the metadata on the array, and so is replicated on all devices. If the word -.B none +.B "none" is given with -.B --grow +.B \-\-grow mode, then any bitmap that is present is removed. To help catch typing errors, the filename must contain at least one @@ -496,11 +517,11 @@ Note: external bitmaps are only known to work on ext2 and ext3. Storing bitmap files on other filesystems may result in serious problems. .TP -.BR --bitmap-chunk= +.BR \-\-bitmap\-chunk= Set the chunksize of the bitmap. Each bit corresponds to that many Kilobytes of storage. When using a file based bitmap, the default is to use the smallest -size that is atleast 4 and requires no more than 2^21 chunks. +size that is at-least 4 and requires no more than 2^21 chunks. When using an .B internal bitmap, the chunksize is automatically determined to make best use of @@ -508,19 +529,19 @@ available space. .TP -.BR -W ", " --write-mostly +.BR \-W ", " \-\-write\-mostly subsequent devices lists in a -.BR --build , -.BR --create , +.BR \-\-build , +.BR \-\-create , or -.B --add +.B \-\-add command will be flagged as 'write-mostly'. This is valid for RAID1 only and means that the 'md' driver will avoid reading from these devices if at all possible. This can be useful if mirroring over a slow link. .TP -.BR --write-behind= +.BR \-\-write\-behind= Specify that write-behind mode should be enabled (valid for RAID1 only). If an argument is specified, it will set the maximum number of outstanding writes allowed. The default value is 256. @@ -529,7 +550,7 @@ mode, and write-behind is only attempted on drives marked as .IR write-mostly . .TP -.BR --assume-clean +.BR \-\-assume\-clean Tell .I mdadm that the array pre-existed and is known to be clean. It can be useful @@ -537,17 +558,19 @@ when trying to recover from a major failure as you can be sure that no data will be affected unless you actually write to the array. It can also be used when creating a RAID1 or RAID10 if you want to avoid the initial resync, however this practice \(em while normally safe \(em is not -recommended. Use this ony if you really know what you are doing. +recommended. Use this only if you really know what you are doing. .TP -.BR --backup-file= -This is needed when --grow is used to increase the number of +.BR \-\-backup\-file= +This is needed when +.B \-\-grow +is used to increase the number of raid-devices in a RAID5 if there are no spare devices available. See the section below on RAID_DEVICE CHANGES. The file should be stored on a separate device, not on the raid array being reshaped. .TP -.BR -N ", " --name= +.BR \-N ", " \-\-name= Set a .B name for the array. This is currently only effective when creating an @@ -555,7 +578,7 @@ array with a version-1 superblock. The name is a simple textual string that can be used to identify array components when assembling. .TP -.BR -R ", " --run +.BR \-R ", " \-\-run Insist that .I mdadm run the array, even if some of the components @@ -565,7 +588,7 @@ will ask for confirmation before including such components in an array. This option causes that question to be suppressed. .TP -.BR -f ", " --force +.BR \-f ", " \-\-force Insist that .I mdadm accept the geometry and layout specified without question. Normally @@ -573,12 +596,12 @@ accept the geometry and layout specified without question. Normally will not allow creation of an array with only one device, and will try to create a raid5 array with one missing drive (as this makes the initial resync work faster). With -.BR --force , +.BR \-\-force , .I mdadm will not try to be so clever. .TP -.BR -a ", " "--auto{=no,yes,md,mdp,part,p}{NN}" +.BR \-a ", " "\-\-auto{=no,yes,md,mdp,part,p}{NN}" Instruct mdadm to create the device file if needed, possibly allocating an unused minor number. "md" causes a non-partitionable array to be used. "mdp", "part" or "p" causes a partitionable array (2.6 and @@ -587,18 +610,20 @@ a 'standard' format, and the type and minor number will be determined from this. See DEVICE NAMES below. The argument can also come immediately after -"-a". e.g. "-ap". +"\-a". e.g. "\-ap". -If --auto is not given on the command line or in the config file, then +If +.B \-\-auto +is not given on the command line or in the config file, then the default will be -.BR --auto=yes . +.BR \-\-auto=yes . If -.I --scan +.B \-\-scan is also given, then any .I auto= entries in the config file will override the -.I --auto +.B \-\-auto instruction given on the command line. For partitionable arrays, @@ -606,7 +631,7 @@ For partitionable arrays, will create the device file for the whole array and for the first 4 partitions. A different number of partitions can be specified at the end of this option (e.g. -.BR --auto=p7 ). +.BR \-\-auto=p7 ). If the device name ends with a digit, the partition names add a 'p', and a number, e.g. "/dev/home1p3". If there is no trailing digit, then the partition names just have a number added, @@ -621,9 +646,9 @@ number, and there is no entry in /dev for that number and with a non-standard name. .TP -.BR --symlink = no +.BR \-\-symlink = no Normally when -.B --auto +.B \-\-auto causes .I mdadm to create devices in @@ -635,9 +660,9 @@ with names starting with or .BR md_ . Use -.B --symlink=no +.B \-\-symlink=no to suppress this, or -.B --symlink=yes +.B \-\-symlink=yes to enforce this even if it is suppressing .IR mdadm.conf . @@ -645,84 +670,85 @@ to enforce this even if it is suppressing .SH For assemble: .TP -.BR -u ", " --uuid= +.BR \-u ", " \-\-uuid= uuid of array to assemble. Devices which don't have this uuid are excluded .TP -.BR -m ", " --super-minor= +.BR \-m ", " \-\-super\-minor= Minor number of device that array was created for. Devices which don't have this minor number are excluded. If you create an array as /dev/md1, then all superblocks will contain the minor number 1, even if the array is later assembled as /dev/md2. Giving the literal word "dev" for -.B --super-minor +.B \-\-super\-minor will cause .I mdadm to use the minor number of the md device that is being assembled. e.g. when assembling .BR /dev/md0 , -.M --super-minor=dev +.M \-\-super\-minor=dev will look for super blocks with a minor number of 0. .TP -.BR -N ", " --name= +.BR \-N ", " \-\-name= Specify the name of the array to assemble. This must be the name that was specified when creating the array. It must either match -then name stored in the superblock exactly, or it must match +the name stored in the superblock exactly, or it must match with the current .I homehost -is added to the start of the given name. +prefixed to the start of the given name. .TP -.BR -f ", " --force +.BR \-f ", " \-\-force Assemble the array even if some superblocks appear out-of-date .TP -.BR -R ", " --run +.BR \-R ", " \-\-run Attempt to start the array even if fewer drives were given than were present last time the array was active. Normally if not all the expected drives are found and -.B --scan +.B \-\-scan is not used, then the array will be assembled but not started. With -.B --run +.B \-\-run an attempt will be made to start it anyway. .TP -.B --no-degraded +.B \-\-no\-degraded This is the reverse of -.B --run -in that it inhibits the started if array unless all expected drives +.B \-\-run +in that it inhibits the startup of array unless all expected drives are present. This is only needed with -.B --scan -and can be used if you physical connections to devices are +.B \-\-scan, +and can be used if the physical connections to devices are not as reliable as you would like. .TP -.BR -a ", " "--auto{=no,yes,md,mdp,part}" +.BR \-a ", " "\-\-auto{=no,yes,md,mdp,part}" See this option under Create and Build options. .TP -.BR -b ", " --bitmap= +.BR \-b ", " \-\-bitmap= Specify the bitmap file that was given when the array was created. If an array has an .B internal bitmap, there is no need to specify this when assembling the array. .TP -.BR --backup-file= +.BR \-\-backup\-file= If -.B --backup-file +.B \-\-backup\-file was used to grow the number of raid-devices in a RAID5, and the system crashed during the critical section, then the same -.B --backup-file -must be presented to --assemble to allow possibly corrupted data to be -restored. +.B \-\-backup\-file +must be presented to +.B \-\-assemble +to allow possibly corrupted data to be restored. .TP -.BR -U ", " --update= +.BR \-U ", " \-\-update= Update the superblock on each device while assembling the array. The argument given to this flag can be one of .BR sparc2.2 , @@ -734,28 +760,28 @@ argument given to this flag can be one of .BR byteorder , .BR devicesize , or -.BR super-minor . +.BR super\-minor . The .B sparc2.2 option will adjust the superblock of an array what was created on a Sparc machine running a patched 2.2 Linux kernel. This kernel got the alignment of part of the superblock wrong. You can use the -.B "--examine --sparc2.2" +.B "\-\-examine \-\-sparc2.2" option to .I mdadm to see what effect this would have. The -.B super-minor +.B super\-minor option will update the .B "preferred minor" field on each superblock to match the minor number of the array being assembled. This can be useful if -.B --examine +.B \-\-examine reports a different "Preferred Minor" to -.BR --detail . +.BR \-\-detail . In some cases this update will be performed automatically by the kernel driver. In particular the update happens automatically at the first write to an array with redundancy (RAID level 1 or @@ -764,10 +790,13 @@ greater) on a 2.6 (or later) kernel. The .B uuid option will change the uuid of the array. If a UUID is given with the -"--uuid" option that UUID will be used as a new UUID and will +.B \-\-uuid +option that UUID will be used as a new UUID and will .B NOT be used to help identify the devices in the array. -If no "--uuid" is given, a random uuid is chosen. +If no +.B \-\-uuid +is given, a random UUID is chosen. The .B name @@ -798,7 +827,7 @@ The option allows arrays to be moved between machines with different byte-order. When assembling such an array for the first time after a move, giving -.B "--update=byteorder" +.B "\-\-update=byteorder" will cause .I mdadm to expect superblocks to have their byteorder reversed, and will @@ -820,135 +849,165 @@ can be used to store data, so if a device in a version 1.1 or 1.2 array becomes larger, the metadata will still be visible, but the extra space will not. In this case it might be useful to assemble the array with -.BR --update=devicesize . +.BR \-\-update=devicesize . This will cause .I mdadm to determine the maximum usable amount of space on each device and update the relevant field in the metadata. .TP -.B --auto-update-homehost -This flag is only meaning with auto-assembly (see discussion below). +.B \-\-auto\-update\-homehost +This flag is only meaningful with auto-assembly (see discussion below). In that situation, if no suitable arrays are found for this homehost, .I mdadm -will recan for any arrays at all and will assemble them and update the +will rescan for any arrays at all and will assemble them and update the homehost to match the current host. .SH For Manage mode: .TP -.BR -a ", " --add +.BR \-a ", " \-\-add hot-add listed devices. .TP -.BR --re-add +.BR \-\-re\-add re-add a device that was recently removed from an array. .TP -.BR -r ", " --remove +.BR \-r ", " \-\-remove remove listed devices. They must not be active. i.e. they should -be failed or spare devices. - -.TP -.BR -f ", " --fail +be failed or spare devices. As well as the name of a device file +(e.g. +.BR /dev/sda1 ) +the words +.B failed +and +.B detached +can be given to +.BR \-\-remove . +The first causes all failed device to be removed. The second causes +any device which is no longer connected to the system (i.e an 'open' +returns +.BR ENXIO ) +to be removed. This will only succeed for devices that are spares or +have already been marked as failed. + +.TP +.BR \-f ", " \-\-fail mark listed devices as faulty. +As well as the name of a device file, the word +.B detached +can be given. This will cause any device that has been detached from +the system to be marked as failed. It can then be removed. .TP -.BR --set-faulty -same as --fail. +.BR \-\-set\-faulty +same as +.BR \-\-fail . .P -Each of these options require that the first device list is the array -to be acted upon and the remainder are component devices to be added, -removed, or marked as fault. Several different operations can be +Each of these options require that the first device listed is the array +to be acted upon, and the remainder are component devices to be added, +removed, or marked as faulty. Several different operations can be specified for different devices, e.g. .in +5 -mdadm /dev/md0 --add /dev/sda1 --fail /dev/sdb1 --remove /dev/sdb1 +mdadm /dev/md0 \-\-add /dev/sda1 \-\-fail /dev/sdb1 \-\-remove /dev/sdb1 .in -5 Each operation applies to all devices listed until the next -operations. +operation. If an array is using a write-intent bitmap, then devices which have been removed can be re-added in a way that avoids a full -reconstruction but instead just updated the blocks that have changed +reconstruction but instead just updates the blocks that have changed since the device was removed. For arrays with persistent metadata (superblocks) this is done automatically. For arrays created with -.B --build +.B \-\-build mdadm needs to be told that this device we removed recently with -.B --re-add. +.BR \-\-re\-add . Devices can only be removed from an array if they are not in active -use. i.e. that must be spares or failed devices. To remove an active -device, it must be marked as -.B faulty -first. +use, i.e. that must be spares or failed devices. To remove an active +device, it must first be marked as +.B faulty. .SH For Misc mode: .TP -.BR -Q ", " --query +.BR \-Q ", " \-\-query Examine a device to see (1) if it is an md device and (2) if it is a component of an md array. Information about what is discovered is presented. .TP -.BR -D ", " --detail +.BR \-D ", " \-\-detail Print detail of one or more md devices. .TP -.BR -E ", " --examine +.BR \-Y ", " \-\-export +When used with +.B \-\-detail +or +.BR \-\-examine , +output will be formatted as +.B key=value +pairs for easy import into the environment. + +.TP +.BR \-E ", " \-\-examine Print content of md superblock on device(s). .TP -.B --sparc2.2 +.B \-\-sparc2.2 If an array was created on a 2.2 Linux kernel patched with RAID support, the superblock will have been created incorrectly, or at least incompatibly with 2.4 and later kernels. Using the -.B --sparc2.2 +.B \-\-sparc2.2 flag with -.B --examine +.B \-\-examine will fix the superblock before displaying it. If this appears to do the right thing, then the array can be successfully assembled using -.BR "--assemble --update=sparc2.2" . +.BR "\-\-assemble \-\-update=sparc2.2" . .TP -.BR -X ", " --examine-bitmap +.BR \-X ", " \-\-examine\-bitmap Report information about a bitmap file. +The argument is either an external bitmap file or an array component +in case of an internal bitmap. .TP -.BR -R ", " --run +.BR \-R ", " \-\-run start a partially built array. .TP -.BR -S ", " --stop +.BR \-S ", " \-\-stop deactivate array, releasing all resources. .TP -.BR -o ", " --readonly +.BR \-o ", " \-\-readonly mark array as readonly. .TP -.BR -w ", " --readwrite +.BR \-w ", " \-\-readwrite mark array as readwrite. .TP -.B --zero-superblock +.B \-\-zero\-superblock If the device contains a valid md superblock, the block is overwritten with zeros. With ---force +.B \-\-force the block where the superblock would be is overwritten even if it doesn't appear to be valid. .TP -.BR -t ", " --test +.BR \-t ", " \-\-test When used with -.BR --detail , +.BR \-\-detail , the exit status of .I mdadm is set to reflect the status of the device. .TP -.BR -W ", " --wait +.BR \-W ", " \-\-wait For each md device given, wait for any resync, recovery, or reshape activity to finish before returning. .I mdadm @@ -957,7 +1016,7 @@ listed, otherwise it will return failure. .SH For Incremental Assembly mode: .TP -.BR --rebuild-map ", " -r +.BR \-\-rebuild\-map ", " \-r Rebuild the map file .RB ( /var/run/mdadm/map ) that @@ -965,14 +1024,14 @@ that uses to help track which arrays are currently being assembled. .TP -.BR --run ", " -R +.BR \-\-run ", " \-R Run any array assembled as soon as a minimal number of devices are available, rather than waiting until all expected devices are present. .TP -.BR --scan ", " -s +.BR \-\-scan ", " \-s Only meaningful with -.B -R +.B \-R this will scan the .B map file for arrays that are being incrementally assembled and will try to @@ -983,46 +1042,46 @@ as requiring an external bitmap, that bitmap will be attached first. .SH For Monitor mode: .TP -.BR -m ", " --mail +.BR \-m ", " \-\-mail Give a mail address to send alerts to. .TP -.BR -p ", " --program ", " --alert +.BR \-p ", " \-\-program ", " \-\-alert Give a program to be run whenever an event is detected. .TP -.BR -y ", " --syslog +.BR \-y ", " \-\-syslog Cause all events to be reported through 'syslog'. The messages have facility of 'daemon' and varying priorities. .TP -.BR -d ", " --delay +.BR \-d ", " \-\-delay Give a delay in seconds. .B mdadm polls the md arrays and then waits this many seconds before polling again. The default is 60 seconds. .TP -.BR -f ", " --daemonise +.BR \-f ", " \-\-daemonise Tell .B mdadm to run as a background daemon if it decides to monitor anything. This causes it to fork and run in the child, and to disconnect form the terminal. The process id of the child is written to stdout. This is useful with -.B --scan +.B \-\-scan which will only continue monitoring if a mail address or alert program is found in the config file. .TP -.BR -i ", " --pid-file +.BR \-i ", " \-\-pid\-file When .B mdadm is running in daemon mode, write the pid of the daemon process to the specified file, instead of printing it on standard output. .TP -.BR -1 ", " --oneshot +.BR \-1 ", " \-\-oneshot Check arrays only once. This will generate .B NewArray events and more significantly @@ -1031,12 +1090,12 @@ and .B SparesMissing events. Running .in +5 -.B " mdadm --monitor --scan -1" +.B " mdadm \-\-monitor \-\-scan \-1" .in -5 from a cron script will ensure regular notification of any degraded arrays. .TP -.BR -t ", " --test +.BR \-t ", " \-\-test Generate a .B TestMessage alert for every array found at startup. This alert gets mailed and @@ -1047,15 +1106,15 @@ message do get through successfully. .HP 12 Usage: -.B mdadm --assemble +.B mdadm \-\-assemble .I md-device options-and-component-devices... .HP 12 Usage: -.B mdadm --assemble --scan +.B mdadm \-\-assemble \-\-scan .I md-devices-and-options... .HP 12 Usage: -.B mdadm --assemble --scan +.B mdadm \-\-assemble \-\-scan .I options... .PP @@ -1064,7 +1123,7 @@ For each array, mdadm needs to know the md device, the identity of the array, and a number of component-devices. These can be found in a number of ways. In the first usage example (without the -.BR --scan ) +.BR \-\-scan ) the first device given is the md device. In the second usage example, all devices listed are treated as md devices and assembly is attempted. @@ -1072,54 +1131,54 @@ In the third (where no devices are listed) all md devices that are listed in the configuration file are assembled. If precisely one device is listed, but -.B --scan +.B \-\-scan is not given, then .I mdadm acts as though -.B --scan -was given and identify information is extracted from the configuration file. +.B \-\-scan +was given and identity information is extracted from the configuration file. The identity can be given with the -.B --uuid +.B \-\-uuid option, with the -.B --super-minor -option, can be found in the config file, or will be taken from the -super block on the first component-device listed on the command line. +.B \-\-super\-minor +option, will be taken from the md-device record in the config file, or +will be taken from the super block of the first component-device +listed on the command line. Devices can be given on the -.B --assemble +.B \-\-assemble command line or in the config file. Only devices which have an md superblock which contains the right identity will be considered for any array. The config file is only used if explicitly named with -.B --config +.B \-\-config or requested with (a possibly implicit) -.B --scan. +.BR \-\-scan . In the later case, .B /etc/mdadm.conf is used. If -.B --scan +.B \-\-scan is not given, then the config file will only be used to find the identity of md arrays. Normally the array will be started after it is assembled. However if -.B --scan +.B \-\-scan is not given and insufficient drives were listed to start a complete (non-degraded) array, then the array is not started (to guard against usage errors). To insist that the array be started in this case (as may work for RAID1, 4, 5, 6, or 10), give the -.B --run +.B \-\-run flag. If the md device does not exist, then it will be created providing the intent is clear. i.e. the name must be in a standard form, or the -.I --auto +.B \-\-auto option must be given to clarify how and whether the device should be created. - This can be useful for handling partitioned devices (which don't have a stable device number \(em it can change after a reboot) and when using "udev" to manage your @@ -1129,7 +1188,7 @@ initialisation conventions). If the option to "auto" is "mdp" or "part" or (on the command line only) "p", then mdadm will create a partitionable array, using the -first free one that is not in use, and does not already have an entry +first free one that is not in use and does not already have an entry in /dev (apart from numeric /dev/md* entries). If the option to "auto" is "yes" or "md" or (on the command line) @@ -1140,7 +1199,7 @@ It is expected that the "auto" functionality will be used to create device entries with meaningful names such as "/dev/md/home" or "/dev/md/root", rather than names based on the numerical array number. -When using this option to create a partitionable array, the device +When using option "auto" to create a partitionable array, the device files for the first 4 partitions are also created. If a different number is required it can be simply appended to the auto option. e.g. "auto=part8". Partition names are created by appending a digit @@ -1148,16 +1207,16 @@ string to the device name, with an intervening "p" if the device name ends with a digit. The -.B --auto +.B \-\-auto option is also available in Build and Create modes. As those modes do not use a config file, the "auto=" config option does not apply to these modes. .SS Auto Assembly When -.B --assemble +.B \-\-assemble is used with -.B --scan +.B \-\-scan and no devices are listed, .I mdadm will first attempt to assemble all the arrays listed in the config @@ -1172,7 +1231,7 @@ anything that it finds which is tagged as belonging to the given homehost. This is the only situation where .I mdadm will assemble arrays without being given specific device name or -identify information for the array. +identity information for the array. If .I mdadm @@ -1188,18 +1247,18 @@ so for example If the array uses version-1 metadata, then the .B name from the superblock is used to similarly create a name in -.BR /dev/md . -The name will have any 'host' prefix stripped first. +.BR /dev/md +(the name will have any 'host' prefix stripped first). If .I mdadm cannot find any array for the given host at all, and if -.B --auto-update-homehost +.B \-\-auto\-update\-homehost is given, then .I mdadm will search again for any array (not just an array created for this host) and will assemble each assuming -.IR --update=homehost . +.BR \-\-update=homehost . This will change the host tag in the superblock so that on the next run, these arrays will be found without the second pass. The intention of this feature is to support transitioning a set of md arrays to using @@ -1213,16 +1272,16 @@ devices from one host to another. .HP 12 Usage: -.B mdadm --build -.I device -.BI --chunk= X -.BI --level= Y -.BI --raid-devices= Z +.B mdadm \-\-build +.I md-device +.BI \-\-chunk= X +.BI \-\-level= Y +.BI \-\-raid\-devices= Z .I devices .PP This usage is similar to -.BR --create . +.BR \-\-create . The difference is that it creates an array without a superblock. With these arrays there is no difference between initially creating the array and subsequently assembling the array, except that hopefully there is useful @@ -1236,12 +1295,12 @@ once complete. .HP 12 Usage: -.B mdadm --create -.I device -.BI --chunk= X -.BI --level= Y +.B mdadm \-\-create +.I md-device +.BI \-\-chunk= X +.BI \-\-level= Y .br -.BI --raid-devices= Z +.BI \-\-raid\-devices= Z .I devices .PP @@ -1249,7 +1308,7 @@ This usage will initialise a new md array, associate some devices with it, and activate the array. If the -.B --auto +.B \-\-auto option is given (as described in more detail in the section on Assemble mode), then the md device will be created with a suitable device number if necessary. @@ -1260,7 +1319,7 @@ device size exceeds 1%. If any discrepancy is found, the array will not automatically be run, though the presence of a -.B --run +.B \-\-run can override this caution. To create a "degraded" array in which some devices are missing, simply @@ -1280,13 +1339,13 @@ will automatically create a degraded array with an extra spare drive. This is because building the spare into a degraded array is in general faster than resyncing the parity on a non-degraded, but not clean, array. This feature can be overridden with the -.I --force +.B \-\-force option. When creating an array with version-1 metadata a name for the host is required. If this is not given with the -.B --name +.B \-\-name option, .I mdadm will chose a name based on the last component of the name of the @@ -1304,30 +1363,32 @@ will be used. A new array will normally get a randomly assigned 128bit UUID which is very likely to be unique. If you have a specific need, you can choose a UUID for the array by giving the -.B --uuid= +.B \-\-uuid= option. Be warned that creating two arrays with the same UUID is a recipe for disaster. Also, using -.B --uuid= +.B \-\-uuid= when creating a v0.90 array will silently override any -.B --homehost= +.B \-\-homehost= setting. -'''If the -'''.B --size -'''option is given, it is not necessary to list any component-devices in this command. -'''They can be added later, before a -'''.B --run. -'''If no -'''.B --size -'''is given, the apparent size of the smallest drive given is used. - -The General Management options that are valid with --create are: -.TP -.B --run +.\"If the +.\".B \-\-size +.\"option is given, it is not necessary to list any component-devices in this command. +.\"They can be added later, before a +.\".B \-\-run. +.\"If no +.\".B \-\-size +.\"is given, the apparent size of the smallest drive given is used. + +The General Management options that are valid with +.B \-\-create +are: +.TP +.B \-\-run insist on running the array even if some devices look like they might be in use. .TP -.B --readonly +.B \-\-readonly start the array readonly \(em not supported yet. @@ -1343,7 +1404,7 @@ This usage will allow individual devices in an array to be failed, removed or added. It is possible to perform multiple operations with on command. For example: .br -.B " mdadm /dev/md0 -f /dev/hda1 -r /dev/hda1 -a /dev/hda1" +.B " mdadm /dev/md0 \-f /dev/hda1 \-r /dev/hda1 \-a /dev/hda1" .br will firstly mark .B /dev/hda1 @@ -1364,20 +1425,20 @@ Usage: MISC mode includes a number of distinct operations that operate on distinct devices. The operations are: .TP ---query +.B \-\-query The device is examined to see if it is (1) an active md array, or (2) a component of an md array. The information discovered is reported. .TP ---detail +.B \-\-detail The device should be an active md device. .B mdadm will display a detailed description of the array. -.B --brief +.B \-\-brief or -.B --scan +.B \-\-scan will cause the output to be less detailed and the format to be suitable for inclusion in .BR /etc/mdadm.conf . @@ -1385,8 +1446,8 @@ The exit status of .I mdadm will normally be 0 unless .I mdadm -failed to get useful information about the device(s). However if the -.B --test +failed to get useful information about the device(s); however, if the +.B \-\-test option is given, then the exit status will be: .RS .TP @@ -1397,62 +1458,61 @@ The array is functioning normally. The array has at least one failed device. .TP 2 -The array has multiple failed devices and hence is unusable (raid4 or -raid5). +The array has multiple failed devices such that it is unusable. .TP 4 There was an error while trying to get information about the device. .RE .TP ---examine +.B \-\-examine The device should be a component of an md array. .B mdadm will read the md superblock of the device and display the contents. If -.B --brief -is given, or -.B --scan -then multiple devices that are components of the one array +.B \-\-brief +or +.B \-\-scan +is given, then multiple devices that are components of the one array are grouped together and reported in a single entry suitable for inclusion in .BR /etc/mdadm.conf . Having -.B --scan +.B \-\-scan without listing any devices will cause all devices listed in the config file to be examined. .TP ---stop +.B \-\-stop The devices should be active md arrays which will be deactivated, as long as they are not currently in use. .TP ---run +.B \-\-run This will fully activate a partially assembled md array. .TP ---readonly +.B \-\-readonly This will mark an active array as read-only, providing that it is not currently being used. .TP ---readwrite +.B \-\-readwrite This will change a .B readonly array back to being read/write. .TP ---scan +.B \-\-scan For all operations except -.BR --examine , -.B --scan +.BR \-\-examine , +.B \-\-scan will cause the operation to be applied to all arrays listed in .BR /proc/mdstat . For -.BR --examine, -.B --scan +.BR \-\-examine, +.B \-\-scan causes all devices listed in the config file to be examined. @@ -1460,7 +1520,7 @@ causes all devices listed in the config file to be examined. .HP 12 Usage: -.B mdadm --monitor +.B mdadm \-\-monitor .I options... devices... .PP @@ -1483,7 +1543,7 @@ If any devices are listed on the command line, .B mdadm will only monitor those devices. Otherwise all arrays listed in the configuration file will be monitored. Further, if -.B --scan +.B \-\-scan is given, then any other md devices that appear in .B /proc/mdstat will also be monitored. @@ -1492,20 +1552,20 @@ The result of monitoring the arrays is the generation of events. These events are passed to a separate program (if specified) and may be mailed to a given E-mail address. -When passing event to program, the program is run once for each event -and is given 2 or 3 command-line arguments. The first is the -name of the event (see below). The second is the name of the +When passing events to a program, the program is run once for each event, +and is given 2 or 3 command-line arguments: the first is the +name of the event (see below), the second is the name of the md device which is affected, and the third is the name of a related -device if relevant, such as a component device that has failed. +device if relevant (such as a component device that has failed). If -.B --scan +.B \-\-scan is given, then a program or an E-mail address must be specified on the command line or in the config file. If neither are available, then .B mdadm will not monitor anything. Without -.B --scan +.B \-\-scan, .B mdadm will continue monitoring as long as something was found to monitor. If no program or email is given, then each event is reported to @@ -1553,7 +1613,7 @@ faulty. (syslog priority: Critical) .TP .B FailSpare A spare component device which was being rebuilt to replace a faulty -device has failed. (syslog priority: Critial) +device has failed. (syslog priority: Critical) .TP .B SpareActive @@ -1575,7 +1635,7 @@ generated when notices a drive failure which causes degradation, but only when .I mdadm notices that an array is degraded when it first sees the array. -(syslog priority: Critial) +(syslog priority: Critical) .TP .B MoveSpare @@ -1591,7 +1651,7 @@ If has been told, via the config file, that an array should have a certain number of spare devices, and .I mdadm -detects that it has fewer that this number when it first sees the +detects that it has fewer than this number when it first sees the array, it will report a .B SparesMissing message. @@ -1600,20 +1660,20 @@ message. .TP .B TestMessage An array was found at startup, and the -.B --test +.B \-\-test flag was given. (syslog priority: Info) .RE Only -.B Fail , -.B FailSpare , -.B DegradedArray , -.B SparesMissing , +.B Fail, +.B FailSpare, +.B DegradedArray, +.B SparesMissing and .B TestMessage cause Email to be sent. All events cause the program to be run. -The program is run with two or three arguments, they being the event +The program is run with two or three arguments: the event name, the array device and possibly a second device. Each event has an associated array device (e.g. @@ -1631,16 +1691,16 @@ the second device is the array that the spare was moved from. For .B mdadm to move spares from one array to another, the different arrays need to -be labelled with the same +be labeled with the same .B spare-group in the configuration file. The .B spare-group -name can be any string. It is only necessary that different spare +name can be any string; it is only necessary that different spare groups use different names. When .B mdadm -detects that an array which is in a spare group has fewer active +detects that an array in a spare group has fewer active devices than necessary for the complete array, and has no spare devices, it will look for another array in the same spare group that has a full complement of working drive and a spare. It will then @@ -1663,7 +1723,7 @@ for RAID1, RAID5 and RAID6. .IP \(bu 4 increase the "raid-disks" attribute of RAID1, RAID5, and RAID6. .IP \(bu 4 -add a write-intent bitmap to any array which support these bitmaps, or +add a write-intent bitmap to any array which supports these bitmaps, or remove a write-intent bitmap from such an array. .PP @@ -1691,7 +1751,7 @@ inactive devices. When reducing the number of devices in a RAID1 array, the slots which are to be removed from the array must already be vacant. That is, the -devices that which were in those slots must be failed and removed. +devices which were in those slots must be failed and removed. When the number of devices is increased, any hot spares that are present will be activated immediately. @@ -1708,16 +1768,16 @@ this "critical section" is reshaped, and takes a backup of the data that is in that section. This backup is normally stored in any spare devices that the array has, however it can also be stored in a separate file specified with the -.B --backup-file +.B \-\-backup\-file option. If this option is used, and the system does crash during the critical period, the same file must be passed to -.B --assemble +.B \-\-assemble to restore the backup and reassemble the array. .SS BITMAP CHANGES A write-intent bitmap can be added to, or removed from, an active -array. Either internal bitmaps, or bitmaps stored in a separate file +array. Either internal bitmaps, or bitmaps stored in a separate file, can be added. Note that if you add a bitmap stored in a file which is in a filesystem that is on the raid array being affected, the system will deadlock. The bitmap must be on a separate filesystem. @@ -1726,28 +1786,28 @@ will deadlock. The bitmap must be on a separate filesystem. .HP 12 Usage: -.B mdadm --incremental -.RB [ --run ] -.RB [ --quiet ] +.B mdadm \-\-incremental +.RB [ \-\-run ] +.RB [ \-\-quiet ] .I component-device .HP 12 Usage: -.B mdadm --incremental --rebuild +.B mdadm \-\-incremental \-\-rebuild .HP 12 Usage: -.B mdadm --incremental --run --scan +.B mdadm \-\-incremental \-\-run \-\-scan .PP This mode is designed to be used in conjunction with a device discovery system. As devices are found in a system, they can be passed to -.B "mdadm --incremental" +.B "mdadm \-\-incremental" to be conditionally added to an appropriate array. .I mdadm performs a number of tests to determine if the device is part of an -array, and which array is should be part of. If an appropriate array +array, and which array it should be part of. If an appropriate array is found, or can be created, .I mdadm adds the device to the array and conditionally starts the array. @@ -1758,13 +1818,13 @@ will only add devices to an array which were previously working (active or spare) parts of that array. It does not currently support automatic inclusion of a new drive as a spare in some array. -.B "mdadm --incremental" -requires a bug present in all kernels through 2.6.19, to be fixed. -Hopefully this will be fixed in 2.6.20. Alternately apply the patch +.B "mdadm \-\-incremental" +requires a bug-fix in all kernels through 2.6.19. +Hopefully, this will be fixed in 2.6.20; alternately, apply the patch which is included with the mdadm source distribution. If .I mdadm detects that this bug is present, it will abort any attempt to use -.BR --incremental . +.BR \-\-incremental . The tests that .I mdadm @@ -1789,9 +1849,9 @@ line. .IP + Does the device have a valid md superblock. If a specific metadata version is request with -.B --metadata +.B \-\-metadata or -.B -e +.B \-e then only that style of metadata is accepted, otherwise .I mdadm finds any known version of metadata. If no @@ -1804,11 +1864,11 @@ The metadata can match in two ways. Either there is an array listed in .B mdadm.conf which identifies the array (either by UUID, by name, by device list, -or by minor-number), the array was created with a +or by minor-number), or the array was created with a .B homehost -specified, and that +specified and that .B homehost -matches that which is given in +matches the one in .B mdadm.conf or on the command line. If @@ -1818,7 +1878,7 @@ current host, the device will be rejected. .IP + .I mdadm -keeps a list of arrays that is has partly assembled in +keeps a list of arrays that it has partially assembled in .B /var/run/mdadm/map (or .B /var/run/mdadm.map @@ -1849,7 +1909,7 @@ there are at least that many, the array will be started. This means that if any devices are missing the array will not be restarted. As an alternative, -.B --run +.B \-\-run may be passed to .B mdadm in which case the array will be run as soon as there are enough @@ -1857,10 +1917,10 @@ devices present for the data to be accessible. For a raid1, that means one device will start the array. For a clean raid5, the array will be started as soon as all but one drive is present. -Note that neither of these approaches is really ideal. If it is can +Note that neither of these approaches is really ideal. If it can be known that all device discovery has completed, then .br -.B " mdadm -IRs" +.B " mdadm \-IRs" .br can be run which will try to start all arrays that are being incrementally assembled. They are started in "read-auto" mode in @@ -1871,48 +1931,48 @@ still be added safely. .SH EXAMPLES -.B " mdadm --query /dev/name-of-device" +.B " mdadm \-\-query /dev/name-of-device" .br This will find out if a given device is a raid array, or is part of one, and will provide brief information about the device. -.B " mdadm --assemble --scan" +.B " mdadm \-\-assemble \-\-scan" .br -This will assemble and start all arrays listed in the standard config file +This will assemble and start all arrays listed in the standard config file. This command will typically go in a system startup file. -.B " mdadm --stop --scan" +.B " mdadm \-\-stop \-\-scan" .br -This will shut down all array that can be shut down (i.e. are not +This will shut down all arrays that can be shut down (i.e. are not currently in use). This will typically go in a system shutdown script. -.B " mdadm --follow --scan --delay=120" +.B " mdadm \-\-follow \-\-scan \-\-delay=120" .br If (and only if) there is an Email address or program given in the standard config file, then monitor the status of all arrays listed in that file by polling them ever 2 minutes. -.B " mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/hd[ac]1" +.B " mdadm \-\-create /dev/md0 \-\-level=1 \-\-raid\-devices=2 /dev/hd[ac]1" .br Create /dev/md0 as a RAID1 array consisting of /dev/hda1 and /dev/hdc1. .br -.B " echo 'DEVICE /dev/hd*[0-9] /dev/sd*[0-9]' > mdadm.conf" +.B " echo 'DEVICE /dev/hd*[0\-9] /dev/sd*[0\-9]' > mdadm.conf" .br -.B " mdadm --detail --scan >> mdadm.conf" +.B " mdadm \-\-detail \-\-scan >> mdadm.conf" .br This will create a prototype config file that describes currently active arrays that are known to be made from partitions of IDE or SCSI drives. This file should be reviewed before being used as it may contain unwanted detail. -.B " echo 'DEVICE /dev/hd[a-z] /dev/sd*[a-z]' > mdadm.conf" +.B " echo 'DEVICE /dev/hd[a\-z] /dev/sd*[a\-z]' > mdadm.conf" .br -.B " mdadm --examine --scan --config=mdadm.conf >> mdadm.conf" -.ber -This will find what arrays could be assembled from existing IDE and -SCSI whole drives (not partitions) and store the information is the +.B " mdadm \-\-examine \-\-scan \-\-config=mdadm.conf >> mdadm.conf" +.br +This will find arrays which could be assembled from existing IDE and +SCSI whole drives (not partitions), and store the information in the format of a config file. This file is very likely to contain unwanted detail, particularly the @@ -1920,16 +1980,16 @@ the entries. It should be reviewed and edited before being used as an actual config file. -.B " mdadm --examine --brief --scan --config=partitions" +.B " mdadm \-\-examine \-\-brief \-\-scan \-\-config=partitions" .br -.B " mdadm -Ebsc partitions" +.B " mdadm \-Ebsc partitions" .br Create a list of devices by reading .BR /proc/partitions , scan these for RAID superblocks, and printout a brief listing of all -that was found. +that were found. -.B " mdadm -Ac partitions -m 0 /dev/md0" +.B " mdadm \-Ac partitions \-m 0 /dev/md0" .br Scan all partitions and devices listed in .BR /proc/partitions @@ -1937,32 +1997,37 @@ and assemble .B /dev/md0 out of all such devices with a RAID superblock with a minor number of 0. -.B " mdadm --monitor --scan --daemonise > /var/run/mdadm" +.B " mdadm \-\-monitor \-\-scan \-\-daemonise > /var/run/mdadm" .br If config file contains a mail address or alert program, run mdadm in the background in monitor mode monitoring all md devices. Also write pid of mdadm daemon to .BR /var/run/mdadm . -.B " mdadm -Iq /dev/somedevice" +.B " mdadm \-Iq /dev/somedevice" .br Try to incorporate newly discovered device into some array as appropriate. -.B " mdadm --incremental --rebuild --run --scan" +.B " mdadm \-\-incremental \-\-rebuild \-\-run \-\-scan" .br Rebuild the array map from any current arrays, and then start any that can be started. -.B " mdadm --create --help" +.B " mdadm /dev/md4 --fail detached --remove detached" +.br +Any devices which are components of /dev/md4 will be marked as faulty +and then remove from the array. + +.B " mdadm \-\-create \-\-help" .br Provide help about the Create mode. -.B " mdadm --config --help" +.B " mdadm \-\-config \-\-help" .br Provide help about the format of the config file. -.B " mdadm --help" +.B " mdadm \-\-help" .br Provide general help. @@ -1978,7 +2043,7 @@ filesystem, lists all active md devices with information about them. .B mdadm uses this to find arrays when -.B --scan +.B \-\-scan is given in Misc mode, and to monitor array reconstruction on Monitor mode. @@ -1993,8 +2058,8 @@ for more details. .SS /var/run/mdadm/map When -.I --incremental -mode is used. this file gets a list of arrays currently being created. +.B \-\-incremental +mode is used, this file gets a list of arrays currently being created. If .B /var/run/mdadm does not exist as a directory, then @@ -2007,11 +2072,11 @@ While entries in the /dev directory can have any format you like, .I mdadm has an understanding of 'standard' formats which it uses to guide its behaviour when creating device files via the -.I --auto +.B \-\-auto option. The standard names for non-partitioned arrays (the only sort of md -array available in 2.4 and earlier) either of +array available in 2.4 and earlier) are either of .IP /dev/mdNN .br @@ -2019,7 +2084,7 @@ array available in 2.4 and earlier) either of .PP where NN is a number. The standard names for partitionable arrays (as available from 2.6 -onwards) is one of +onwards) are either of .IP /dev/md/dNN .br @@ -2040,26 +2105,30 @@ package, and does not use the configuration file at all. .SH SEE ALSO -For information on the various levels of -RAID, check out: +For further information on MD and the various levels of +RAID, see: .IP -.UR http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/ -http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/ +.UR http://unthought.net/Software-RAID.HOWTO/ +http://unthought.net/Software\-RAID.HOWTO/ +.UE +.IP +.UR http://linux-raid.osdl.org/ +http://linux\-raid.osdl.org/ .UE -'''.PP -'''for new releases of the RAID driver check out: -''' -'''.IP -'''.UR ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches -'''ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches -'''.UE -'''.PP -'''or -'''.IP -'''.UR http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ -'''http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ -'''.UE +.\".PP +.\"for new releases of the RAID driver check out: +.\" +.\".IP +.\".UR ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches +.\"ftp://ftp.kernel.org/pub/linux/kernel/people/mingo/raid-patches +.\".UE +.\".PP +.\"or +.\".IP +.\".UR http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ +.\"http://www.cse.unsw.edu.au/~neilb/patches/linux-stable/ +.\".UE .PP The latest version of .I mdadm