diff options
Diffstat (limited to 'mdadm.8.in')
| -rw-r--r-- | mdadm.8.in | 142 |
1 files changed, 117 insertions, 25 deletions
@@ -5,7 +5,7 @@ .\" 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 "" v4.0 +.TH MDADM 8 "" v4.1-rc1 .SH NAME mdadm \- manage MD devices .I aka @@ -126,7 +126,7 @@ of component devices and changing the number of active devices in Linear and RAID levels 0/1/4/5/6, changing the RAID level between 0, 1, 5, and 6, and between 0 and 10, changing the chunk size and layout for RAID 0,4,5,6,10 as well as adding or -removing a write-intent bitmap. +removing a write-intent bitmap and changing the array's consistency policy. .TP .B "Incremental Assembly" @@ -267,13 +267,13 @@ the exact meaning of this option in different contexts. .TP .BR \-c ", " \-\-config= Specify the config file or directory. Default is to use -.B /etc/mdadm/mdadm.conf +.B /etc/mdadm.conf and -.BR /etc/mdadm/mdadm.conf.d , +.BR /etc/mdadm.conf.d , or if those are missing then -.B /etc/mdadm.conf +.B /etc/mdadm/mdadm.conf and -.BR /etc/mdadm.conf.d . +.BR /etc/mdadm/mdadm.conf.d . If the config file given is .B "partitions" then nothing will be read, but @@ -541,6 +541,8 @@ A value of restores the apparent size of the array to be whatever the real amount of available space is. +Clustered arrays do not support this parameter yet. + .TP .BR \-c ", " \-\-chunk= Specify chunk size of kilobytes. The default when creating an @@ -724,7 +726,9 @@ When creating an array on devices which are 100G or larger, .I mdadm automatically adds an internal bitmap as it will usually be beneficial. This can be suppressed with -.B "\-\-bitmap=none". +.B "\-\-bitmap=none" +or by selecting a different consistency policy with +.BR \-\-consistency\-policy . .TP .BR \-\-bitmap\-chunk= @@ -923,7 +927,8 @@ will not try to be so clever. Start the array .B read only rather than read-write as normal. No writes will be allowed to the -array, and no resync, recovery, or reshape will be started. +array, and no resync, recovery, or reshape will be started. It works with +Create, Assemble, Manage and Misc mode. .TP .BR \-a ", " "\-\-auto{=yes,md,mdp,part,p}{NN}" @@ -1015,6 +1020,45 @@ simultaneously. If not specified, this defaults to 4. Specify journal device for the RAID-4/5/6 array. The journal device should be a SSD with reasonable lifetime. +.TP +.BR \-\-symlinks +Auto creation of symlinks in /dev to /dev/md, option --symlinks must +be 'no' or 'yes' and work with --create and --build. + +.TP +.BR \-k ", " \-\-consistency\-policy= +Specify how the array maintains consistency in case of unexpected shutdown. +Only relevant for RAID levels with redundancy. +Currently supported options are: +.RS + +.TP +.B resync +Full resync is performed and all redundancy is regenerated when the array is +started after unclean shutdown. + +.TP +.B bitmap +Resync assisted by a write-intent bitmap. Implicitly selected when using +.BR \-\-bitmap . + +.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 +.BR \-\-write\-journal . + +.TP +.B ppl +For RAID5 only, Partial Parity Log is used to close the write hole and +eliminate resync. PPL is stored in the metadata region of RAID member drives, +no additional journal drive is needed. + +.PP +Can be used with \-\-grow to change the consistency policy of an active array +in some cases. See CONSISTENCY POLICY CHANGES below. +.RE + .SH For assemble: @@ -1139,6 +1183,8 @@ argument given to this flag can be one of .BR no\-bitmap , .BR bbl , .BR no\-bbl , +.BR ppl , +.BR no\-ppl , .BR metadata , or .BR super\-minor . @@ -1218,7 +1264,8 @@ is correct. The .B byteorder option allows arrays to be moved between machines with different -byte-order. +byte-order, such as from a big-endian machine like a Sparc or some +MIPS machines, to a little-endian x86_64 machine. When assembling such an array for the first time after a move, giving .B "\-\-update=byteorder" will cause @@ -1279,6 +1326,16 @@ option will cause any reservation of space for a bad block list to be removed. If the bad block list contains entries, this will fail, as removing the list could cause data corruption. +The +.B ppl +option will enable PPL for a RAID5 array and reserve space for PPL on each +device. There must be enough free space between the data and superblock and a +write-intent bitmap or journal must not be used. + +The +.B no\-ppl +option will disable PPL in the superblock. + .TP .BR \-\-freeze\-reshape Option is intended to be used in start-up scripts during initrd boot phase. @@ -1291,6 +1348,10 @@ Reshape can be continued later using the .B \-\-continue option for the grow command. +.TP +.BR \-\-symlinks +See this option under Create and Build options. + .SH For Manage mode: .TP @@ -1465,9 +1526,8 @@ the device is found or <slot>:missing in case the device is not found. .TP .BR \-\-add-journal -Recreate journal for RAID-4/5/6 array that lost a journal device. In the -current implementation, this command cannot add a journal to an array -that had a failed journal. To avoid interrupting on-going write opertions, +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, .B \-\-add-journal only works for array in Read-Only state. @@ -1631,6 +1691,10 @@ overwritten with zeros. With 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. + .TP .B \-\-kill\-subarray= If the device is a container and the argument to \-\-kill\-subarray @@ -1888,9 +1952,9 @@ The config file is only used if explicitly named with or requested with (a possibly implicit) .BR \-\-scan . In the later case, -.B /etc/mdadm/mdadm.conf -or .B /etc/mdadm.conf +or +.B /etc/mdadm/mdadm.conf is used. If @@ -2144,12 +2208,14 @@ in the array exceed 100G is size, an internal write-intent bitmap will automatically be added unless some other option is explicitly requested with the .B \-\-bitmap -option. In any case space for a bitmap will be reserved so that one -can be added layer with +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 +can be added later with .BR "\-\-grow \-\-bitmap=internal" . -If the metadata type supports it (currently only 1.x metadata), space -will be allocated to store a bad block list. This allows a modest +If the metadata type supports it (currently only 1.x and IMSM metadata), +space will be allocated to store a bad block list. This allows a modest number of bad blocks to be recorded, allowing the drive to remain in service while only partially functional. @@ -2173,7 +2239,7 @@ be in use. .TP .B \-\-readonly -start the array readonly \(em not supported yet. +start the array in readonly mode. .SH MANAGE MODE .HP 12 @@ -2284,9 +2350,11 @@ superblock field in the subarray. Similar to updating an array in .B \-U or .B \-\-update= -option. Currently only -.B name -is supported. +option. The supported options are +.BR name , +.B ppl +and +.BR no\-ppl . The .B name @@ -2297,6 +2365,13 @@ re\-assembled. If updating would change the UUID of an active subarray this operation is blocked, and the command will end in an error. +The +.B ppl +and +.B no\-ppl +options enable and disable PPL in the metadata. Currently supported only for +IMSM subarrays. + .TP .B \-\-examine The device should be a component of an md array. @@ -2630,6 +2705,8 @@ RAID0, RAID4, and RAID5, and between RAID0 and RAID10 (in the near-2 mode). .IP \(bu 4 add a write-intent bitmap to any array which supports these bitmaps, or remove a write-intent bitmap from such an array. +.IP \(bu 4 +change the array's consistency policy. .PP Using GROW on containers is currently supported only for Intel's IMSM @@ -2685,6 +2762,11 @@ 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. +.PP +Note: +.B "--grow --size" +is not yet supported for external file bitmap. + .SS RAID\-DEVICES CHANGES A RAID1 array can work with any number of devices from 1 upwards @@ -2786,6 +2868,16 @@ 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. +.SS CONSISTENCY POLICY CHANGES + +The consistency policy of an active array can be changed by using the +.B \-\-consistency\-policy +option in Grow mode. Currently this works only for the +.B ppl +and +.B resync +policies and allows to enable or disable the RAID5 Partial Parity Log (PPL). + .SH INCREMENTAL MODE .HP 12 @@ -2864,7 +2956,7 @@ This is the only context where the aliases are used. They are usually provided by a .I udev rules mentioning -.BR ${DEVLINKS} . +.BR $env{DEVLINKS} . .IP + Does the device have a valid md superblock? If a specific metadata @@ -3184,7 +3276,7 @@ uses this to find arrays when is given in Misc mode, and to monitor array reconstruction on Monitor mode. -.SS /etc/mdadm/mdadm.conf (or /etc/mdadm.conf) +.SS /etc/mdadm.conf The config file lists which devices may be scanned to see if they contain MD super block, and gives identifying information @@ -3192,7 +3284,7 @@ they contain MD super block, and gives identifying information .BR mdadm.conf (5) for more details. -.SS /etc/mdadm/mdadm.conf.d (or /etc/mdadm.conf.d) +.SS /etc/mdadm.conf.d A directory containing configuration files which are read in lexical order. |