diff options
Diffstat (limited to '')
| -rw-r--r-- | mdadm.8.in | 178 |
1 files changed, 88 insertions, 90 deletions
@@ -158,7 +158,7 @@ adding new spares and removing faulty devices. .B Misc 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. +information-gathering operations. .\"This mode allows operations on independent devices such as examine MD .\"superblocks, erasing old superblocks and stopping active arrays. @@ -231,12 +231,12 @@ mode to be assumed. .TP .BR \-h ", " \-\-help -Display general help message or, after one of the above options, a +Display a general help message or, after one of the above options, a mode-specific help message. .TP .B \-\-help\-options -Display more detailed help about command line parsing and some commonly +Display more detailed help about command-line parsing and some commonly used options. .TP @@ -266,7 +266,7 @@ the exact meaning of this option in different contexts. .TP .BR \-c ", " \-\-config= -Specify the config file or directory. If not specified, default config file +Specify the config file or directory. If not specified, the default config file and default conf.d directory will be used. See .BR mdadm.conf (5) for more details. @@ -379,7 +379,7 @@ When creating an array, the .B homehost will be recorded in the metadata. For version-1 superblocks, it will 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 +the SHA1 hash of the hostname will be stored in the latter half of the UUID. When reporting information about an array, any array which is tagged @@ -388,7 +388,7 @@ for the given homehost will be reported as such. When using Auto-Assemble, only arrays tagged for the given homehost will be allowed to use 'local' names (i.e. not ending in '_' followed by a digit string). See below under -.BR "Auto Assembly" . +.BR "Auto-Assembly" . The special name "\fBany\fP" can be used as a wild card. If an array is created with @@ -403,7 +403,7 @@ When .I mdadm needs to print the name for a device it normally finds the name in .B /dev -which refers to the device and is shortest. When a path component is +which refers to the device and is the shortest. When a path component is given with .B \-\-prefer .I mdadm @@ -478,9 +478,9 @@ still be larger than any replacement. This option can be used with .B \-\-create -for determining initial size of an array. For external metadata, +for determining the initial size of an array. For external metadata, it can be used on a volume, but not on a container itself. -Setting initial size of +Setting the initial size of .B RAID 0 array is only valid for external metadata. @@ -545,20 +545,20 @@ Clustered arrays do not support this parameter yet. .TP .BR \-c ", " \-\-chunk= -Specify chunk size of kilobytes. The default when creating an +Specify chunk size in kilobytes. The default when creating an array is 512KB. To ensure compatibility with earlier versions, the default when building an array with no persistent metadata is 64KB. This is only meaningful for RAID0, RAID4, RAID5, RAID6, and RAID10. RAID4, RAID5, RAID6, and RAID10 require the chunk size to be a power -of 2. In any case it must be a multiple of 4KB. +of 2, with minimal chunk size being 4KB. A suffix of 'K', 'M', 'G' or 'T' can be given to indicate Kilobytes, Megabytes, Gigabytes or Terabytes respectively. .TP .BR \-\-rounding= -Specify rounding factor for a Linear array. The size of each +Specify the rounding factor for a Linear array. The size of each component will be rounded down to a multiple of this size. This is a synonym for .B \-\-chunk @@ -655,7 +655,8 @@ option to set subsequent failure modes. and "flush" will clear any persistent faults. 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: +by a small number signifying the number of copies of each datablock. +The default is 'n2'. The supported options are: .I 'n' signals 'near' copies. Multiple copies of one data block are at @@ -673,7 +674,7 @@ signals 'far' copies (multiple copies have very different offsets). See md(4) for more detail about 'near', 'offset', and 'far'. -The number is the number of copies of each datablock. 2 is normal, 3 +As for the number of copies of each data block, 2 is normal, 3 can be useful. This number can be at most equal to the number of devices in the array. It does not need to divide evenly into that number (e.g. it is perfectly legal to have an 'n2' layout for an array @@ -684,7 +685,7 @@ A bug introduced in Linux 3.14 means that RAID0 arrays started using a different layout. This could lead to data corruption. Since Linux 5.4 (and various stable releases that received backports), the kernel will not accept such an array unless -a layout is explictly set. It can be set to +a layout is explicitly set. It can be set to .RB ' original ' or .RB ' alternate '. @@ -760,13 +761,13 @@ or by selecting a different consistency policy with .TP .BR \-\-bitmap\-chunk= -Set the chunksize of the bitmap. Each bit corresponds to that many +Set the chunk size 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 at-least 4 and requires no more than 2^21 chunks. +When using a file-based bitmap, the default is to use the smallest +size that is at least 4 and requires no more than 2^21 chunks. When using an .B internal -bitmap, the chunksize defaults to 64Meg, or larger if necessary to +bitmap, the chunk size defaults to 64Meg, or larger if necessary to fit the bitmap into the available space. A suffix of 'K', 'M', 'G' or 'T' can be given to indicate Kilobytes, @@ -840,7 +841,7 @@ can be used with that command to avoid the automatic resync. .BR \-\-backup\-file= This is needed when .B \-\-grow -is used to increase the number of raid-devices in a RAID5 or RAID6 if +is used to increase the number of raid devices in a RAID5 or RAID6 if there are no spare devices available, or to shrink, change RAID level or layout. See the GROW MODE section below on RAID\-DEVICES CHANGES. The file must be stored on a separate device, not on the RAID array @@ -879,7 +880,7 @@ When creating an array, .B \-\-data\-offset can be specified as .BR variable . -In the case each member device is expected to have a offset appended +In the case each member device is expected to have an offset appended to the name, separated by a colon. This makes it possible to recreate exactly an array which has varying data offsets (as can happen when different versions of @@ -943,7 +944,7 @@ Insist that .I mdadm accept the geometry and layout specified without question. Normally .I mdadm -will not allow creation of an array with only one device, and will try +will not allow the 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 , @@ -1004,7 +1005,7 @@ number added, e.g. If the md device name is in a 'standard' format as described in DEVICE NAMES, then it will be created, if necessary, with the appropriate device number based on that name. If the device name is not in one of these -formats, then a unused device number will be allocated. The device +formats, then an unused device number will be allocated. The device number will be considered unused if there is no active array for that number, and there is no entry in /dev for that number and with a non-standard name. Names that are not in 'standard' format are only @@ -1032,25 +1033,25 @@ then .B \-\-add can be used to add some extra devices to be included in the array. In most cases this is not needed as the extra devices can be added as -spares first, and then the number of raid-disks can be changed. -However for RAID0, it is not possible to add spares. So to increase +spares first, and then the number of raid disks can be changed. +However, for RAID0 it is not possible to add spares. So to increase the number of devices in a RAID0, it is necessary to set the new number of devices, and to add the new devices, in the same command. .TP .BR \-\-nodes -Only works when the array is for clustered environment. It specifies +Only works when the array is created for a clustered environment. It specifies the maximum number of nodes in the cluster that will use this device simultaneously. If not specified, this defaults to 4. .TP .BR \-\-write-journal Specify journal device for the RAID-4/5/6 array. The journal device -should be a SSD with reasonable lifetime. +should be an SSD with a reasonable lifetime. .TP .BR \-k ", " \-\-consistency\-policy= -Specify how the array maintains consistency in case of unexpected shutdown. +Specify how the array maintains consistency in the case of an unexpected shutdown. Only relevant for RAID levels with redundancy. Currently supported options are: .RS @@ -1058,7 +1059,7 @@ Currently supported options are: .TP .B resync Full resync is performed and all redundancy is regenerated when the array is -started after unclean shutdown. +started after an unclean shutdown. .TP .B bitmap @@ -1067,8 +1068,8 @@ Resync assisted by a write-intent bitmap. Implicitly selected when using .TP .B journal -For RAID levels 4/5/6, journal device is used to log transactions and replay -after unclean shutdown. Implicitly selected when using +For RAID levels 4/5/6, the journal device is used to log transactions and replay +after an unclean shutdown. Implicitly selected when using .BR \-\-write\-journal . .TP @@ -1237,7 +1238,7 @@ This can be useful if reports a different "Preferred Minor" to .BR \-\-detail . In some cases this update will be performed automatically -by the kernel driver. In particular the update happens automatically +by the kernel driver. In particular, the update happens automatically at the first write to an array with redundancy (RAID level 1 or greater) on a 2.6 (or later) kernel. @@ -1277,7 +1278,7 @@ For version-1 superblocks, this involves updating the name. The .B home\-cluster option will change the cluster name as recorded in the superblock and -bitmap. This option only works for clustered environment. +bitmap. This option only works for a clustered environment. The .B resync @@ -1390,10 +1391,10 @@ This option should be used with great caution. .TP .BR \-\-freeze\-reshape -Option is intended to be used in start-up scripts during initrd boot phase. -When array under reshape is assembled during initrd phase, this option -stops reshape after reshape critical section is being restored. This happens -before file system pivot operation and avoids loss of file system context. +This option is intended to be used in start-up scripts during the initrd boot phase. +When the array under reshape is assembled during the initrd phase, this option +stops the reshape after the reshape-critical section has been restored. This happens +before the file system pivot operation and avoids loss of filesystem context. Losing file system context would cause reshape to be broken. Reshape can be continued later using the @@ -1437,9 +1438,9 @@ re\-add a device that was previously removed from an array. If the metadata on the device reports that it is a member of the array, and the slot that it used is still vacant, then the device will be added back to the array in the same position. This will normally -cause the data for that device to be recovered. However based on the +cause the data for that device to be recovered. However, based on the event count on the device, the recovery may only require sections that -are flagged a write-intent bitmap to be recovered or may not require +are flagged by a write-intent bitmap to be recovered or may not require any recovery at all. When used on an array that has no metadata (i.e. it was built with @@ -1447,13 +1448,12 @@ When used on an array that has no metadata (i.e. it was built with it will be assumed that bitmap-based recovery is enough to make the device fully consistent with the array. -When used with v1.x metadata, .B \-\-re\-add -can be accompanied by +can also be accompanied by .BR \-\-update=devicesize , .BR \-\-update=bbl ", or" .BR \-\-update=no\-bbl . -See the description of these option when used in Assemble mode for an +See descriptions of these options when used in Assemble mode for an explanation of their use. If the device name given is @@ -1480,7 +1480,7 @@ Add a device as a spare. This is similar to except that it does not attempt .B \-\-re\-add first. The device will be added as a spare even if it looks like it -could be an recent member of the array. +could be a recent member of the array. .TP .BR \-r ", " \-\-remove @@ -1497,12 +1497,12 @@ and names like .B set-A can be given to .BR \-\-remove . -The first causes all failed device to be removed. The second causes +The first causes all failed devices 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. -The third will remove a set as describe below under +The third will remove a set as described below under .BR \-\-fail . .TP @@ -1519,7 +1519,7 @@ For RAID10 arrays where the number of copies evenly divides the number of devices, the devices can be conceptually divided into sets where each set contains a single complete copy of the data on the array. Sometimes a RAID10 array will be configured so that these sets are on -separate controllers. In this case all the devices in one set can be +separate controllers. In this case, all the devices in one set can be failed by giving a name like .B set\-A or @@ -1549,9 +1549,9 @@ This can follow a list of .B \-\-replace devices. The devices listed after .B \-\-with -will be preferentially used to replace the devices listed after +will preferentially be used to replace the devices listed after .BR \-\-replace . -These device must already be spare devices in the array. +These devices must already be spare devices in the array. .TP .BR \-\-write\-mostly @@ -1574,8 +1574,8 @@ the device is found or <slot>:missing in case the device is not found. .TP .BR \-\-add-journal -Add journal to an existing array, or recreate journal for RAID-4/5/6 array -that lost a journal device. To avoid interrupting on-going write opertions, +Add a journal to an existing array, or recreate journal for a RAID-4/5/6 array +that lost a journal device. To avoid interrupting ongoing write operations, .B \-\-add-journal only works for array in Read-Only state. @@ -1631,9 +1631,9 @@ Print details of one or more md devices. .TP .BR \-\-detail\-platform Print details of the platform's RAID capabilities (firmware / hardware -topology) for a given metadata format. If used without argument, mdadm +topology) for a given metadata format. If used without an argument, mdadm will scan all controllers looking for their capabilities. Otherwise, mdadm -will only look at the controller specified by the argument in form of an +will only look at the controller specified by the argument in the form of an absolute filepath or a link, e.g. .IR /sys/devices/pci0000:00/0000:00:1f.2 . @@ -1742,8 +1742,8 @@ the block where the superblock would be is overwritten even if it doesn't appear to be valid. .B Note: -Be careful to call \-\-zero\-superblock with clustered raid, make sure -array isn't used or assembled in other cluster node before execute it. +Be careful when calling \-\-zero\-superblock with clustered raid. Make sure +the array isn't used or assembled in another cluster node before executing it. .TP .B \-\-kill\-subarray= @@ -1790,7 +1790,7 @@ For each md device given, or each device in /proc/mdstat if is given, arrange for the array to be marked clean as soon as possible. .I mdadm will return with success if the array uses external metadata and we -successfully waited. For native arrays this returns immediately as the +successfully waited. For native arrays, this returns immediately as the kernel handles dirty-clean transitions at shutdown. No action is taken if safe-mode handling is disabled. @@ -1830,7 +1830,7 @@ uses to help track which arrays are currently being assembled. .TP .BR \-\-run ", " \-R -Run any array assembled as soon as a minimal number of devices are +Run any array assembled as soon as a minimal number of devices is available, rather than waiting until all expected devices are present. .TP @@ -1860,7 +1860,7 @@ Only used with \-\-fail. The 'path' given will be recorded so that if a new device appears at the same location it can be automatically added to the same array. This allows the failed device to be automatically replaced by a new device without metadata if it appears -at specified path. This option is normally only set by a +at specified path. This option is normally only set by an .I udev script. @@ -1961,7 +1961,7 @@ Usage: .PP This usage assembles one or more RAID arrays from pre-existing components. 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. +array, and the number of component devices. These can be found in a number of ways. In the first usage example (without the .BR \-\-scan ) @@ -2001,7 +2001,7 @@ The config file is only used if explicitly named with .B \-\-config or requested with (a possibly implicit) .BR \-\-scan . -In the later case, default config file is used. See +In the latter case, the default config file is used. See .BR mdadm.conf (5) for more details. @@ -2039,14 +2039,14 @@ detects that udev is not configured, it will create the devices in .B /dev itself. -In Linux kernels prior to version 2.6.28 there were two distinctly -different types of md devices that could be created: one that could be +In Linux kernels prior to version 2.6.28 there were two distinct +types of md devices that could be created: one that could be partitioned using standard partitioning tools and one that could not. -Since 2.6.28 that distinction is no longer relevant as both type of +Since 2.6.28 that distinction is no longer relevant as both types of devices can be partitioned. .I mdadm will normally create the type that originally could not be partitioned -as it has a well defined major number (9). +as it has a well-defined major number (9). Prior to 2.6.28, it is important that mdadm chooses the correct type of array device to use. This can be controlled with the @@ -2066,7 +2066,7 @@ can also be given in the configuration file as a word starting .B auto= on the ARRAY line for the relevant array. -.SS Auto Assembly +.SS Auto-Assembly When .B \-\-assemble is used with @@ -2122,11 +2122,11 @@ See .IR mdadm.conf (5) for further details. -Note: Auto assembly cannot be used for assembling and activating some +Note: Auto-assembly cannot be used for assembling and activating some arrays which are undergoing reshape. In particular as the .B backup\-file -cannot be given, any reshape which requires a backup-file to continue -cannot be started by auto assembly. An array which is growing to more +cannot be given, any reshape which requires a backup file to continue +cannot be started by auto-assembly. An array which is growing to more devices and has passed the critical section can be assembled using auto-assembly. @@ -2233,7 +2233,7 @@ When creating a partition based array, using .I mdadm with version-1.x metadata, the partition type should be set to .B 0xDA -(non fs-data). This type selection allows for greater precision since +(non fs-data). This type of selection allows for greater precision since using any other [RAID auto-detect (0xFD) or a GNU/Linux partition (0x83)], might create problems in the event of array recovery through a live cdrom. @@ -2249,7 +2249,7 @@ when creating a v0.90 array will silently override any setting. .\"If the .\".B \-\-size -.\"option is given, it is not necessary to list any component-devices in this command. +.\"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 @@ -2263,7 +2263,7 @@ requested with the .B \-\-bitmap option or a different consistency policy is selected with the .B \-\-consistency\-policy -option. In any case space for a bitmap will be reserved so that one +option. In any case, space for a bitmap will be reserved so that one can be added later with .BR "\-\-grow \-\-bitmap=internal" . @@ -2313,7 +2313,7 @@ will firstly mark as faulty in .B /dev/md0 and will then remove it from the array and finally add it back -in as a spare. However only one md array can be affected by a single +in as a spare. However, only one md array can be affected by a single command. When a device is added to an active array, mdadm checks to see if it @@ -2458,14 +2458,14 @@ config file to be examined. If the device contains RAID metadata, a file will be created in the .I directory and the metadata will be written to it. The file will be the same -size as the device and have the metadata written in the file at the -same locate that it exists in the device. However the file will be "sparse" so +size as the device and will have the metadata written at the +same location as it exists in the device. However, the file will be "sparse" so that only those blocks containing metadata will be allocated. The total space used will be small. -The file name used in the +The filename used in the .I directory -will be the base name of the device. Further if any links appear in +will be the base name of the device. Further, if any links appear in .I /dev/disk/by-id which point to the device, then hard links to the file will be created in @@ -2567,7 +2567,7 @@ and if the destination array has a failed drive but no spares. If any devices are listed on the command line, .I mdadm -will only monitor those devices. Otherwise all arrays listed in the +will only monitor those devices, otherwise, all arrays listed in the configuration file will be monitored. Further, if .B \-\-scan is given, then any other md devices that appear in @@ -2624,10 +2624,10 @@ check, repair). (syslog priority: Warning) .BI Rebuild NN Where .I NN -is a two-digit number (ie. 05, 48). This indicates that rebuild -has passed that many percent of the total. The events are generated -with fixed increment since 0. Increment size may be specified with -a commandline option (default is 20). (syslog priority: Warning) +is a two-digit number (eg. 05, 48). This indicates that the rebuild +has reached that percentage of the total. The events are generated +at a fixed increment from 0. The increment size may be specified with +a command-line option (the default is 20). (syslog priority: Warning) .TP .B RebuildFinished @@ -2735,8 +2735,8 @@ When 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 -attempt to remove the spare from the second drive and add it to the +has a full complement of working drives and a spare. It will then +attempt to remove the spare from the second array and add it to the first. If the removal succeeds but the adding fails, then it is added back to the original array. @@ -2750,10 +2750,8 @@ and then follow similar steps as above if a matching spare is found. .SH GROW MODE The GROW mode is used for changing the size or shape of an active array. -For this to work, the kernel must support the necessary change. -Various types of growth are being added during 2.6 development. -Currently the supported changes include +During the kernel 2.6 era the following changes were added: .IP \(bu 4 change the "size" attribute for RAID1, RAID4, RAID5 and RAID6. .IP \(bu 4 @@ -2796,8 +2794,8 @@ use more than half of a spare device for backup space. .SS SIZE CHANGES Normally when an array is built the "size" is taken from the smallest -of the drives. If all the small drives in an arrays are, one at a -time, removed and replaced with larger drives, then you could have an +of the drives. If all the small drives in an arrays are, over time, +removed and replaced with larger drives, then you could have an array of large drives with only a small amount used. In this situation, changing the "size" with "GROW" mode will allow the extra space to start being used. If the size is increased in this way, a @@ -2812,7 +2810,7 @@ after growing, or to reduce its size .B prior to shrinking the array. -Also the size of an array cannot be changed while it has an active +Also, the size of an array cannot be changed while it has an active bitmap. If an array has a bitmap, it must be removed before the size can be changed. Once the change is complete a new bitmap can be created. @@ -2892,7 +2890,7 @@ long time. A is required. If the array is not simultaneously being grown or shrunk, so that the array size will remain the same - for example, reshaping a 3-drive RAID5 into a 4-drive RAID6 - the backup file will -be used not just for a "cricital section" but throughout the reshape +be used not just for a "critical section" but throughout the reshape operation, as described below under LAYOUT CHANGES. .SS CHUNK-SIZE AND LAYOUT CHANGES @@ -2910,7 +2908,7 @@ slowly. If the reshape is interrupted for any reason, this backup file must be made available to .B "mdadm --assemble" -so the array can be reassembled. Consequently the file cannot be +so the array can be reassembled. Consequently, the file cannot be stored on the device being reshaped. |