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Diffstat (limited to 'man/lvm.8.in')
| -rw-r--r-- | man/lvm.8.in | 346 |
1 files changed, 210 insertions, 136 deletions
diff --git a/man/lvm.8.in b/man/lvm.8.in index 37ebdab..2ce0065 100644 --- a/man/lvm.8.in +++ b/man/lvm.8.in @@ -5,18 +5,18 @@ lvm \- LVM2 tools .B lvm [command | file] .SH DESCRIPTION -\fBlvm\fP provides the command-line tools for LVM2. A separate +lvm provides the command-line tools for LVM2. A separate manual page describes each command in detail. .LP If \fBlvm\fP is invoked with no arguments it presents a readline prompt (assuming it was compiled with readline support). -LVM commands may be entered interactively at this prompt with -readline facilities including history and command name and option +LVM commands may be entered interactively at this prompt with +readline facilities including history and command name and option completion. Refer to \fBreadline\fP(3) for details. .LP If \fBlvm\fP is invoked with argv[0] set to the name of a specific -LVM command (for example by using a hard or soft link) it acts as -that command. +LVM command (for example by using a hard or soft link) it acts as +that command. .LP On invocation, \fBlvm\fP requires that only the standard file descriptors stdin, stdout and stderr are available. If others are found, they @@ -24,16 +24,16 @@ get closed and messages are issued warning about the leak. .LP Where commands take VG or LV names as arguments, the full path name is optional. An LV called "lvol0" in a VG called "vg0" can be specified -as "vg0/lvol0". Where a list of VGs is required but is left empty, +as "vg0/lvol0". Where a list of VGs is required but is left empty, a list of all VGs will be substituted. Where a list of LVs is required but a VG is given, a list of all the LVs in that VG will be substituted. -So "lvdisplay vg0" will display all the LVs in "vg0". -Tags can also be used - see \fBaddtag\fP below. +So \fBlvdisplay vg0\fP will display all the LVs in "vg0". +Tags can also be used - see \fB\-\-addtag\fP below. .LP -One advantage of using the built-in shell is that configuration -information gets cached internally between commands. +One advantage of using the built-in shell is that configuration +information gets cached internally between commands. .LP -A file containing a simple script with one command per line +A file containing a simple script with one command per line can also be given on the command line. The script can also be executed directly if the first line is #! followed by the absolute path of \fBlvm\fP. @@ -41,8 +41,8 @@ path of \fBlvm\fP. The following commands are built into lvm without links normally being created in the filesystem for them. .TP -\fBdumpconfig\fP \(em Display the configuration information after -loading \fBlvm.conf\fP (5) and any other configuration files. +\fBdumpconfig\fP \(em Display the configuration information after +loading \fBlvm.conf\fP(5) and any other configuration files. .TP \fBformats\fP \(em Display recognised metadata formats. .TP @@ -50,234 +50,309 @@ loading \fBlvm.conf\fP (5) and any other configuration files. .TP \fBpvdata\fP \(em Not implemented in LVM2. .TP -\fBsegtypes\fP \(em Display recognised logical volume segment types. +\fBsegtypes\fP \(em Display recognised Logical Volume segment types. .TP \fBversion\fP \(em Display version information. .LP .SH COMMANDS The following commands implement the core LVM functionality. .TP -\fBpvchange\fP \(em Change attributes of a physical volume. +\fBpvchange\fP \(em Change attributes of a Physical Volume. .TP -\fBpvck\fP \(em Check physical volume metadata. +\fBpvck\fP \(em Check Physical Volume metadata. .TP \fBpvcreate\fP \(em Initialize a disk or partition for use by LVM. .TP -\fBpvdisplay\fP \(em Display attributes of a physical volume. +\fBpvdisplay\fP \(em Display attributes of a Physical Volume. .TP -\fBpvmove\fP \(em Move physical extents. +\fBpvmove\fP \(em Move Physical Extents. .TP -\fBpvremove\fP \(em Remove a physical volume. +\fBpvremove\fP \(em Remove a Physical Volume. .TP \fBpvresize\fP \(em Resize a disk or partition in use by LVM2. .TP -\fBpvs\fP \(em Report information about physical volumes. +\fBpvs\fP \(em Report information about Physical Volumes. .TP -\fBpvscan\fP \(em Scan all disks for physical volumes. +\fBpvscan\fP \(em Scan all disks for Physical Volumes. .TP -\fBvgcfgbackup\fP \(em Backup volume group descriptor area. +\fBvgcfgbackup\fP \(em Backup Volume Group descriptor area. .TP -\fBvgcfgrestore\fP \(em Restore volume group descriptor area. +\fBvgcfgrestore\fP \(em Restore Volume Group descriptor area. .TP -\fBvgchange\fP \(em Change attributes of a volume group. +\fBvgchange\fP \(em Change attributes of a Volume Group. .TP -\fBvgck\fP \(em Check volume group metadata. +\fBvgck\fP \(em Check Volume Group metadata. .TP -\fBvgconvert\fP \(em Convert volume group metadata format. +\fBvgconvert\fP \(em Convert Volume Group metadata format. .TP -\fBvgcreate\fP \(em Create a volume group. +\fBvgcreate\fP \(em Create a Volume Group. .TP -\fBvgdisplay\fP \(em Display attributes of volume groups. +\fBvgdisplay\fP \(em Display attributes of Volume Groups. .TP -\fBvgexport\fP \(em Make volume groups unknown to the system. +\fBvgexport\fP \(em Make volume Groups unknown to the system. .TP -\fBvgextend\fP \(em Add physical volumes to a volume group. +\fBvgextend\fP \(em Add Physical Volumes to a Volume Group. .TP -\fBvgimport\fP \(em Make exported volume groups known to the system. +\fBvgimport\fP \(em Make exported Volume Groups known to the system. .TP -\fBvgimportclone\fP \(em Import and rename duplicated volume group (e.g. a hardware snapshot). +\fBvgimportclone\fP \(em Import and rename duplicated Volume Group (e.g. a hardware snapshot). .TP -\fBvgmerge\fP \(em Merge two volume groups. +\fBvgmerge\fP \(em Merge two Volume Groups. .TP -\fBvgmknodes\fP \(em Recreate volume group directory and logical volume special files +\fBvgmknodes\fP \(em Recreate Volume Group directory and Logical Volume special files .TP -\fBvgreduce\fP \(em Reduce a volume group by removing one or more physical volumes. +\fBvgreduce\fP \(em Reduce a Volume Group by removing one or more +Physical Volumes. .TP -\fBvgremove\fP \(em Remove a volume group. +\fBvgremove\fP \(em Remove a Volume Group. .TP -\fBvgrename\fP \(em Rename a volume group. +\fBvgrename\fP \(em Rename a Volume Group. .TP -\fBvgs\fP \(em Report information about volume groups. +\fBvgs\fP \(em Report information about Volume Groups. .TP -\fBvgscan\fP \(em Scan all disks for volume groups and rebuild caches. +\fBvgscan\fP \(em Scan all disks for Volume Groups and rebuild caches. .TP -\fBvgsplit\fP \(em Split a volume group into two, moving any logical volumes from one volume group to another by moving entire physical volumes. +\fBvgsplit\fP \(em Split a Volume Group into two, moving any logical +volumes from one Volume Group to another by moving entire Physical +Volumes. .TP -\fBlvchange\fP \(em Change attributes of a logical volume. +\fBlvchange\fP \(em Change attributes of a Logical Volume. .TP -\fBlvconvert\fP \(em Convert a logical volume from linear to mirror or snapshot. +\fBlvconvert\fP \(em Convert a Logical Volume from linear to mirror or snapshot. .TP -\fBlvcreate\fP \(em Create a logical volume in an existing volume group. +\fBlvcreate\fP \(em Create a Logical Volume in an existing Volume Group. .TP -\fBlvdisplay\fP \(em Display attributes of a logical volume. +\fBlvdisplay\fP \(em Display attributes of a Logical Volume. .TP -\fBlvextend\fP \(em Extend the size of a logical volume. +\fBlvextend\fP \(em Extend the size of a Logical Volume. .TP -\fBlvmchange\fP \(em Change attributes of the logical volume manager. +\fBlvmchange\fP \(em Change attributes of the Logical Volume Manager. .TP \fBlvmdiskscan\fP \(em Scan for all devices visible to LVM2. .TP \fBlvmdump\fP \(em Create lvm2 information dumps for diagnostic purposes. .TP -\fBlvreduce\fP \(em Reduce the size of a logical volume. +\fBlvreduce\fP \(em Reduce the size of a Logical Volume. .TP -\fBlvremove\fP \(em Remove a logical volume. +\fBlvremove\fP \(em Remove a Logical Volume. .TP -\fBlvrename\fP \(em Rename a logical volume. +\fBlvrename\fP \(em Rename a Logical Volume. .TP -\fBlvresize\fP \(em Resize a logical volume. +\fBlvresize\fP \(em Resize a Logical Volume. .TP -\fBlvs\fP \(em Report information about logical volumes. +\fBlvs\fP \(em Report information about Logical Volumes. .TP -\fBlvscan\fP \(em Scan (all disks) for logical volumes. +\fBlvscan\fP \(em Scan (all disks) for Logical Volumes. .TP The following commands are not implemented in LVM2 but might be in the future: lvmsadc, lvmsar, pvdata. .SH OPTIONS -The following options are available for many of the commands. -They are implemented generically and documented here rather +The following options are available for many of the commands. +They are implemented generically and documented here rather than repeated on individual manual pages. .TP -\fB-h | --help\fP \(em Display the help text. +.BR \-h ", " \-\-help +Display the help text. .TP -\fB--version\fP \(em Display version information. +.B \-\-version +Display version information. .TP -\fB-v | --verbose\fP \(em Set verbose level. -Repeat from 1 to 3 times to increase the detail of messages -sent to stdout and stderr. Overrides config file setting. +.BR \-v ", " \-\-verbose +Set verbose level. Repeat from 1 to 3 times to increase the detail +of messages sent to stdout and stderr. Overrides config file setting. .TP -\fB-d | --debug\fP \(em Set debug level. -Repeat from 1 to 6 times to increase the detail of messages sent -to the log file and/or syslog (if configured). +.BR \-d ", " \-\-debug +Set debug level. Repeat from 1 to 6 times to increase the detail of +messages sent to the log file and/or syslog (if configured). Overrides config file setting. .TP -\fB--quiet\fP \(em Suppress output and log messages. -Overrides -d and -v. +.BR \-q ", " \-\-quiet +Suppress output and log messages. +Overrides \fB\-d\fP and \fB\-v\fP. .TP -\fB-t | --test\fP \(em Run in test mode. -Commands will not update metadata. +.BR \-t ", " \-\-test +Run in test mode. Commands will not update metadata. This is implemented by disabling all metadata writing but nevertheless returning success to the calling function. This may lead to unusual error messages in multi-stage operations if a tool relies on reading back metadata it believes has changed but hasn't. .TP -\fB--driverloaded\fP { \fBy\fP | \fBn\fP } +.BR \-\-driverloaded " {" \fIy | \fIn } Whether or not the device-mapper kernel driver is loaded. -If you set this to \fBn\fP, no attempt will be made to contact the driver. +If you set this to \fIn\fP, no attempt will be made to contact the driver. .TP -\fB-A | --autobackup\fP { \fBy\fP | \fBn\fP } -Whether or not to metadata should be backed up automatically after a change. +.BR \-A ", " \-\-autobackup " {" \fIy | \fIn } +Whether or not to metadata should be backed up automatically after a change. You are strongly advised not to disable this! -See -.B vgcfgbackup (8). +See \fBvgcfgbackup\fP(8). .TP -\fB-P | --partial\fP -When set, the tools will do their best to provide access to volume groups -that are only partially available (one or more physical volumes belonging -to the volume group are missing from the system). Where part of a logical +.BR \-P ", " \-\-partial +When set, the tools will do their best to provide access to Volume Groups +that are only partially available (one or more Physical Volumes belonging +to the Volume Group are missing from the system). Where part of a logical volume is missing, \fB/dev/ioerror\fP will be substituted, and you could use -\fBdmsetup (8)\fP to set this up to return I/O errors when accessed, +\fBdmsetup\fP(8) to set this up to return I/O errors when accessed, or create it as a large block device of nulls. Metadata may not be -changed with this option. To insert a replacement physical volume -of the same or large size use \fBpvcreate -u\fP to set the uuid to -match the original followed by \fBvgcfgrestore (8)\fP. +changed with this option. To insert a replacement Physical Volume +of the same or large size use \fBpvcreate \-u\fP to set the uuid to +match the original followed by \fBvgcfgrestore\fP(8). .TP -\fB-M | --metadatatype type\fP -Specifies which type of on-disk metadata to use, such as \fBlvm1\fP -or \fBlvm2\fP, which can be abbreviated to \fB1\fP or \fB2\fP respectively. -The default (lvm2) can be changed by setting \fBformat\fP in the \fBglobal\fP -section of the config file. +.BR \-M ", " \-\-metadatatype " " \fIType +Specifies which type of on-disk metadata to use, such as \fIlvm1\fP +or \fIlvm2\fP, which can be abbreviated to \fI1\fP or \fI2\fP respectively. +The default (\fIlvm2\fP) can be changed by setting \fBformat\fP +in the \fBglobal\fP section of the config file. .TP -\fB--ignorelockingfailure\fP +.B \-\-ignorelockingfailure This lets you proceed with read-only metadata operations such as -\fBlvchange -ay\fP and \fBvgchange -ay\fP even if the locking module fails. -One use for this is in a system init script if the lock directory +\fBlvchange \-ay\fP and \fBvgchange \-ay\fP even if the locking module fails. +One use for this is in a system init script if the lock directory is mounted read-only when the script runs. .TP -\fB--addtag tag\fP -Add the tag \fBtag\fP to a PV, VG or LV. +.B \-\-addtag \fITag +Add the tag \fITag\fP to a PV, VG or LV. Supply this argument multiple times to add more than one tag at once. -A tag is a word that can be used to group LVM2 objects of the same type -together. -Tags can be given on the command line in place of PV, VG or LV +A tag is a word that can be used to group LVM2 objects of the same type +together. +Tags can be given on the command line in place of PV, VG or LV arguments. Tags should be prefixed with @ to avoid ambiguity. Each tag is expanded by replacing it with all objects possessing that tag which are of the type expected by its position on the command line. PVs can only possess tags while they are part of a Volume Group: PV tags are discarded if the PV is removed from the VG. -As an example, you could tag some LVs as \fBdatabase\fP and others -as \fBuserdata\fP and then activate the database ones -with \fBlvchange -ay @database\fP. +As an example, you could tag some LVs as \fBdatabase\fP and others +as \fBuserdata\fP and then activate the database ones +with \fBlvchange \-ay @database\fP. Objects can possess multiple tags simultaneously. Only the new LVM2 metadata format supports tagging: objects using the LVM1 metadata format cannot be tagged because the on-disk format does not support it. -Snapshots cannot be tagged. -Characters allowed in tags are: A-Z a-z 0-9 _ + . - and -as of version 2.02.78 the following characters are also -accepted: / = ! : # & +Characters allowed in tags are: +.B A-Z a-z 0-9 _ + . - +and as of version 2.02.78 the following characters are also accepted: +.B / = ! : # & .TP -\fB--deltag tag\fP -Delete the tag \fBtag\fP from a PV, VG or LV, if it's present. +.B \-\-deltag \fITag +Delete the tag \fITag\fP from a PV, VG or LV, if it's present. Supply this argument multiple times to remove more than one tag at once. .TP -\fB--alloc AllocationPolicy\fP -The allocation policy to use: \fBcontiguous\fP, \fBcling\fP, \fBnormal\fP, \fBanywhere\fP or \fBinherit\fP. -When a command needs to allocate physical extents from the volume group, -the allocation policy controls how they are chosen. -Each volume group and logical volume has an allocation policy. -The default for a volume group is \fBnormal\fP which applies +.B \-\-alloc \fIAllocationPolicy +The allocation policy to use: +.IR contiguous , +.IR cling , +.IR normal , +.IR anywhere " or" +.IR inherit . +When a command needs to allocate Physical Extents from the Volume Group, +the allocation policy controls how they are chosen. +Each Volume Group and Logical Volume has an allocation policy defined. +The default for a Volume Group is \fInormal\fP which applies common-sense rules such as not placing parallel stripes on the same -physical volume. The default for a logical volume is \fBinherit\fP -which applies the same policy as for the volume group. These policies can -be changed using \fBlvchange\fP (8) and \fBvgchange\fP (8) or over-ridden +Physical Volume. The default for a Logical Volume is \fIinherit\fP +which applies the same policy as for the Volume Group. These policies can +be changed using \fBlvchange\fP(8) and \fBvgchange\fP(8) or overridden on the command line of any command that performs allocation. -The \fBcontiguous\fP policy requires that new extents be placed adjacent -to existing extents. -The \fBcling\fP policy places new extents on the same physical -volume as existing extents in the same stripe of the Logical Volume. -If there are sufficient free extents to satisfy -an allocation request but \fBnormal\fP doesn't use them, -\fBanywhere\fP will - even if that reduces performance by -placing two stripes on the same physical volume. -.IP -N.B. The policies described above are not implemented fully yet. -In particular, contiguous free space cannot be broken up to -satisfy allocation attempts. +The \fIcontiguous\fP policy requires that new Physical Extents be placed adjacent +to existing Physical Extents. +The \fIcling\fP policy places new Physical Extents on the same Physical +Volume as existing Physical Extents in the same stripe of the Logical Volume. +If there are sufficient free Physical Extents to satisfy +an allocation request but \fInormal\fP doesn't use them, +\fIanywhere\fP will - even if that reduces performance by +placing two stripes on the same Physical Volume. .SH ENVIRONMENT VARIABLES .TP -\fBLVM_SYSTEM_DIR\fP -Directory containing lvm.conf and other LVM -system files. -Defaults to "#DEFAULT_SYS_DIR#". +.B HOME +Directory containing \fI.lvm_history\fP if the internal readline +shell is invoked. .TP -\fBHOME\fP -Directory containing .lvm_history if the internal readline shell -is invoked. +.B LVM_SYSTEM_DIR +Directory containing \fBlvm.conf\fP(5) and other LVM system files. +Defaults to "#DEFAULT_SYS_DIR#". .TP -\fBLVM_VG_NAME\fP -The volume group name that is assumed for -any reference to a logical volume that doesn't specify a path. +.B LVM_VG_NAME +The Volume Group name that is assumed for +any reference to a Logical Volume that doesn't specify a path. Not set by default. .SH VALID NAMES The following characters are valid for VG and LV names: -\fBa-z A-Z 0-9 + _ . -\fP +.B a-z A-Z 0-9 + _ . - .LP VG and LV names cannot begin with a hyphen. There are also various reserved names that are used internally by lvm that can not be used as LV or VG names. A VG cannot be called anything that exists in /dev/ at the time of creation, nor can it be called '.' or '..'. -A LV cannot be called '.' '..' 'snapshot' or 'pvmove'. The LV name may also not contain the strings '_mlog' or '_mimage' +A LV cannot be called '.' '..' 'snapshot' or 'pvmove'. The LV name may also not contain +the strings '_mlog', '_mimage', '_rimage', '_tdata', '_tmeta'. +.SH ALLOCATION +When an operation needs to allocate Physical Extents for one or more +Logical Volumes, the tools proceed as follows: + +First of all, they generate the complete set of unallocated Physical Extents +in the Volume Group. If any ranges of Physical Extents are supplied at +the end of the command line, only unallocated Physical Extents within +those ranges on the specified Physical Volumes are considered. + +Then they try each allocation policy in turn, starting with the strictest +policy (\fIcontiguous\fP) and ending with the allocation policy specified +using \fB\-\-alloc\fP or set as the default for the particular Logical +Volume or Volume Group concerned. For each policy, working from the +lowest-numbered Logical Extent of the empty Logical Volume space that +needs to be filled, they allocate as much space as possible according to +the restrictions imposed by the policy. If more space is needed, +they move on to the next policy. + +The restrictions are as follows: + +\fIContiguous\fP requires that the physical location of any Logical +Extent that is not the first Logical Extent of a Logical Volume is +adjacent to the physical location of the Logical Extent immediately +preceding it. + +\fICling\fP requires that the Physical Volume used for any Logical +Extent to be added to an existing Logical Volume is already in use by at +least one Logical Extent earlier in that Logical Volume. If the +configuration parameter allocation/cling_tag_list is defined, then two +Physical Volumes are considered to match if any of the listed tags is +present on both Physical Volumes. This allows groups of Physical +Volumes with similar properties (such as their physical location) to be +tagged and treated as equivalent for allocation purposes. +When a Logical Volume is striped or mirrored, the above restrictions are +applied independently to each stripe or mirror image (leg) that needs +space. +\fINormal\fP will not choose a Physical Extent that shares the same Physical +Volume as a Logical Extent already allocated to a parallel Logical +Volume (i.e. a different stripe or mirror image/leg) at the same offset +within that parallel Logical Volume. + +When allocating a mirror log at the same time as Logical Volumes to hold +the mirror data, Normal will first try to select different Physical +Volumes for the log and the data. If that's not possible and the +allocation/mirror_logs_require_separate_pvs configuration parameter is +set to 0, it will then allow the log to share Physical Volume(s) with +part of the data. + +When allocating thin pool metadata, similar considerations to those of a +mirror log in the last paragraph apply based on the value of the +allocation/thin_pool_metadata_require_separate_pvs configuration +parameter. + +If you rely upon any layout behaviour beyond that documented here, be +aware that it might change in future versions of the code. + +For example, if you supply on the command line two empty Physical +Volumes that have an identical number of free Physical Extents available for +allocation, the current code considers using each of them in the order +they are listed, but there is no guarantee that future releases will +maintain that property. If it is important to obtain a specific layout +for a particular Logical Volume, then you should build it up through a +sequence of \fBlvcreate\fP(8) and \fBlvconvert\fP(8) steps such that the +restrictions described above applied to each step leave the tools no +discretion over the layout. + +To view the way the allocation process currently works in any specific +case, read the debug logging output, for example by adding \-vvvv to +a command. .SH DIAGNOSTICS All tools return a status code of zero on success or non-zero on failure. .SH FILES @@ -325,4 +400,3 @@ All tools return a status code of zero on success or non-zero on failure. .BR vgsplit (8), .BR readline (3), .BR lvm.conf (5) - |