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LVM(8)                                                                  LVM(8)



NAME
       lvm -- LVM2 tools

SYNOPSIS
       lvm [command|file]

DESCRIPTION
       lvm provides the command-line tools for LVM2.  A separate manual page describes each command in detail.

       If  lvm is invoked with no arguments it presents a readline prompt (assuming it was compiled with readline sup-
       port).  LVM commands may be entered interactively at this prompt with readline facilities including history and
       command name and option completion.  Refer to readline(3) for details.

       If  lvm  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.

       On invocation, lvm requires that only the standard file descriptors stdin, stdout and stderr are available.  If
       others  are  found,  they  get closed and messages are issued warning about the leak.  This warning can be sup-
       pressed by setting the environment variable LVM_SUPPRESS_FD_WARNINGS.

       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, 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 --addtag
       below.

       One advantage of using the built-in shell is that configuration information gets cached internally between com-
       mands.

       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 lvm.

BUILT-IN COMMANDS
       The following commands are built into lvm without links normally being created in the filesystem for them.

       config        The same as lvmconfig(8) below.
       devtypes      Display the recognised built-in block device types.
       dumpconfig    The same as lvmconfig(8) below.
       formats       Display recognised metadata formats.
       help          Display the help text.
       lvpoll        Complete lvmpolld operations (Internal command).
       pvdata        Not implemented in LVM2.
       segtypes      Display recognised Logical Volume segment types.
       systemid      Display any system ID currently set on this host.
       tags          Display any tags defined on this host.
       version       Display version information.

COMMANDS
       The following commands implement the core LVM functionality.

       pvchange      Change attributes of a Physical Volume.
       pvck          Check Physical Volume metadata.
       pvcreate      Initialize a disk or partition for use by LVM.
       pvdisplay     Display attributes of a Physical Volume.
       pvmove        Move Physical Extents.
       pvremove      Remove a Physical Volume.
       pvresize      Resize a disk or partition in use by LVM2.
       pvs           Report information about Physical Volumes.
       pvscan        Scan all disks for Physical Volumes.
       vgcfgbackup   Backup Volume Group descriptor area.
       vgcfgrestore  Restore Volume Group descriptor area.
       vgchange      Change attributes of a Volume Group.
       vgck          Check Volume Group metadata.
       vgconvert     Convert Volume Group metadata format.
       vgcreate      Create a Volume Group.
       vgdisplay     Display attributes of Volume Groups.
       vgexport      Make volume Groups unknown to the system.
       vgextend      Add Physical Volumes to a Volume Group.
       vgimport      Make exported Volume Groups known to the system.
       vgimportclone Import and rename duplicated Volume Group (e.g. a hardware snapshot).
       vgmerge       Merge two Volume Groups.
       vgmknodes     Recreate Volume Group directory and Logical Volume special files
       vgreduce      Reduce a Volume Group by removing one or more Physical Volumes.
       vgremove      Remove a Volume Group.
       vgrename      Rename a Volume Group.
       vgs           Report information about Volume Groups.
       vgscan        Scan all disks for Volume Groups and rebuild caches.
       vgsplit       Split a Volume Group into two, moving any logical volumes from one Volume  Group  to  another  by
                     moving entire Physical Volumes.
       lvchange      Change attributes of a Logical Volume.
       lvconvert     Convert a Logical Volume from linear to mirror or snapshot.
       lvcreate      Create a Logical Volume in an existing Volume Group.
       lvdisplay     Display attributes of a Logical Volume.
       lvextend      Extend the size of a Logical Volume.
       lvmchange     Change attributes of the Logical Volume Manager.
       lvmconfig     Display  the  configuration  information  after  loading  lvm.conf(5) and any other configuration
                     files.
       lvmdiskscan   Scan for all devices visible to LVM2.
       lvmdump       Create lvm2 information dumps for diagnostic purposes.
       lvreduce      Reduce the size of a Logical Volume.
       lvremove      Remove a Logical Volume.
       lvrename      Rename a Logical Volume.
       lvresize      Resize a Logical Volume.
       lvs           Report information about Logical Volumes.
       lvscan        Scan (all disks) for Logical Volumes.

       The following commands are not implemented in LVM2 but might be in the future: lvmsadc, lvmsar, pvdata.

OPTIONS
       The following options are available for many of the commands.  They are implemented generically and  documented
       here rather than repeated on individual manual pages.

       Additional hyphens within option names are ignored.  For example, --readonly and --read-only are both accepted.

       -h|-?|--help
              Display the help text.

       --version
              Display version information.

       -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.

       -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.

       -q|--quiet
              Suppress output and log messages.  Overrides -d and -v.  Repeat once to also suppress any  prompts  with
              answer 'no'.

       --yes
              Don't  prompt  for confirmation interactively but instead always assume the answer is 'yes'.  Take great
              care if you use this!

       -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 mes-
              sages in multi-stage operations if a tool relies on reading back metadata it believes  has  changed  but
              hasn't.

       --driverloaded {y|n}
              Whether or not the device-mapper kernel driver is loaded.  If you set this to n, no attempt will be made
              to contact the driver.

       -A|--autobackup {y|n}
              Whether or not to metadata should be backed up automatically after a change.  You are  strongly  advised
              not to disable this!  See vgcfgbackup(8).

       -P|--partial
              When set, the tools will do their best to provide access to Volume Groups that are only partially avail-
              able (one or more Physical Volumes belonging to the Volume Group are missing from  the  system).   Where
              part  of  a logical volume is missing, /dev/ioerror will be substituted, and you could use dmsetup(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 pvcreate -u to set the uuid to match the original followed by vgcfgrestore(8).

       -S|--select Selection
              For reporting commands, display only rows that match Selection criteria.  All rows  are  displayed  with
              the  additional  "selected" column (-o selected) showing 1 if the row matches the Selection and 0 other-
              wise. For non-reporting commands which process LVM entities, the selection can be used to match items to
              process.  See  SELECTION CRITERIA section of this man page for more information about the way the selec-
              tion criteria are constructed.

       -M|--metadatatype Type
              Specifies which type of on-disk metadata to use, such as lvm1 or lvm2, which can be abbreviated to 1  or
              2 respectively.  The default (lvm2) can be changed by setting format in the global section of the config
              file lvm.conf(5).

       --ignorelockingfailure
              This lets you proceed with read-only metadata operations such as lvchange -ay and vgchange -ay  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.

       --ignoreskippedcluster
              Use to avoid exiting with an non-zero status code if the command is run without  clustered  locking  and
              some clustered Volume Groups have to be skipped over.

       --readonly
              Run the command in a special read-only mode which will read on-disk metadata without needing to take any
              locks.  This can be used to peek inside metadata used by a  virtual  machine  image  while  the  virtual
              machine  is  running.   It  can also be used to peek inside the metadata of clustered Volume Groups when
              clustered locking is not configured or running.  No attempt will be made to communicate with the device-
              mapper  kernel driver, so this option is unable to report whether or not Logical Volumes are actually in
              use.

       --foreign
              Cause the command to access foreign VGs, that would otherwise be skipped.  It can be used to  report  or
              display  a  VG that is owned by another host.  This option can cause a command to perform poorly because
              lvmetad caching is not used and metadata is read from disks.

       --shared
              Cause the command to access shared VGs, that would otherwise be skipped when lvmlockd is not being used.
              It  can be used to report or display a lockd VG without locking. Applicable only if LVM is compiled with
              lockd support.

       --addtag Tag
              Add the tag Tag 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 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 database and others as userdata and then activate the database ones with lvchange -ay  @database.
              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.
              Characters  allowed  in tags are: A-Z a-z 0-9 _ + . - and as of version 2.02.78 the following characters
              are also accepted: / = ! : # &.

       --deltag Tag
              Delete the tag Tag from a PV, VG or LV, if it's present.  Supply this argument multiple times to  remove
              more than one tag at once.

       --alloc {anywhere|contiguous|cling|inherit|normal}
              Selects  the  allocation policy when a command needs to allocate Physical Extents from the Volume Group.
              Each Volume Group and Logical Volume has an allocation policy defined.  The default for a  Volume  Group
              is  normal  which  applies  common-sense rules such as not placing parallel stripes on the same Physical
              Volume.  The default for a Logical Volume is inherit which applies the same policy  as  for  the  Volume
              Group.   These  policies  can  be changed using lvchange(8) and vgchange(8) or overridden on the command
              line of any command that performs allocation.  The contiguous policy requires that new Physical  Extents
              be  placed  adjacent  to existing Physical Extents.  The cling 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 normal doesn't use them, any-
              where will - even if that reduces performance by placing two stripes on the same Physical Volume.

       --commandprofile ProfileName
              Selects the command configuration profile to use when processing an LVM command.  See  also  lvm.conf(5)
              for more information about command profile config and the way it fits with other LVM configuration meth-
              ods. Using --commandprofile option overrides any command profile specified via LVM_COMMAND_PROFILE envi-
              ronment variable.

       --metadataprofile ProfileName
              Selects  the  metadata configuration profile to use when processing an LVM command.  When using metadata
              profile during Volume Group or Logical Volume creation, the metadata profile name is saved in  metadata.
              When  such  Volume Group or Logical Volume is processed next time, the metadata profile is automatically
              applied and the use of --metadataprofile option is not necessary. See also lvm.conf(5) for more informa-
              tion about metadata profile config and the way it fits with other LVM configuration methods.

       --profile ProfileName
              A short form of --metadataprofile for vgcreate, lvcreate, vgchange and lvchange command and a short form
              of --commandprofile for any other command (with the exception of lvmconfig command where  the  --profile
              has special meaning, see lvmconfig(8) for more information).

       --config ConfigurationString
              Uses the ConfigurationString as direct string representation of the configuration to override the exist-
              ing configuration. The ConfigurationString is of exactly the same format as used in any  LVM  configura-
              tion file. See lvm.conf(5) for more information about direct config override on command line and the way
              it fits with other LVM configuration methods.

VALID NAMES
       The valid characters for VG and LV names are: a-z A-Z 0-9 + _ . -

       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 '..'.  An LV cannot be called '.', '..', 'snapshot' or 'pvmove'.  The  LV
       name  may  also  not  contain  any  of the following strings: '_cdata', '_cmeta', '_corig', '_mlog', '_mimage',
       '_pmspare', '_rimage', '_rmeta', '_tdata', '_tmeta' or '_vorigin'.  A directory bearing the name of each Volume
       Group  is  created  under  /dev  when  any of its Logical Volumes are activated.  Each active Logical Volume is
       accessible from this directory as a symbolic link leading to a device node.  Links or nodes in /dev/mapper  are
       intended  only for internal use and the precise format and escaping might change between releases and distribu-
       tions.  Other software and scripts should use the /dev/VolumeGroupName/LogicalVolumeName format to  reduce  the
       chance  of  needing  amendment  when  the  software  is  updated.  Should you need to process the node names in
       /dev/mapper, you may use dmsetup splitname to separate out the original VG, LV and internal layer names.

UNIQUE NAMES
       VG names should be unique.  vgcreate will produce an error if the specified VG  name  matches  an  existing  VG
       name.   However,  there  are  cases where different VGs with the same name can appear to LVM, e.g. after moving
       disks or changing filters.

       When VGs with the same name exist, commands operating on all VGs will include all of  the  VGs  with  the  same
       name.  If the ambiguous VG name is specified on the command line, the command will produce an error.  The error
       states that multiple VGs exist with the specified name.  To process one of the VGs specifically,  the  --select
       option should be used with the UUID of the intended VG: '--select vg_uuid=<uuid>'.

       An  exception is if all but one of the VGs with the shared name is foreign (see lvmsystemid(7).)  In this case,
       the one VG that is not foreign is assumed to be the intended VG and is processed.


ALLOCATION
       When an operation needs to allocate Physical Extents for one or more Logical Volumes, the tools proceed as fol-
       lows:

       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 (contiguous) and ending with
       the allocation policy specified using --alloc 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:

       Contiguous  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.

       Cling 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 parame-
       ter 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 proper-
       ties (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.

       Normal will not choose a Physical Extent that shares the same Physical Volume as a Logical Extent already allo-
       cated 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/mir-
       ror_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 ver-
       sions 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
       lvcreate(8) and lvconvert(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.

LOGICAL VOLUME TYPES
       Some logical volume types are simple to create and can be done with a single lvcreate(8) command.   The  linear
       and  striped logical volume types are an example of this.  Other logical volume types may require more than one
       command to create.  The cache (lvmcache(7)) and thin provisioning (lvmthin(7)) types are examples of this.

SELECTION CRITERIA
       The selection criteria are a set of statements combined by logical and grouping operators. The  statement  con-
       sists  of  column name for which a set of valid values is defined using comparison operators. For complete list
       of column names (fields) that can be used in selection, see the output of <lvm reporting command> -S help.


   Comparison operators (cmp_op)
       =~     Matching regular expression.
       !~     Not matching regular expression.
       =      Equal to.
       !=     Not equal to.
       >=     Greater than or equal to.
       >      Greater than
       <=     Less than or equal to.
       <      Less than.


   Binary logical operators (cmp_log)
       &&     All fields must match
       ,      All fields must match
       ||     At least one field must match
       #      At least one field must match


   Unary logical operators
       !      Logical negation


   Grouping operators
       (      Left parenthesis
       )      Right parenthesis
       [      List start
       ]      List end
       {      List subset start
       }      List subset end

   Informal grammar specification
       STATEMENT = column cmp_op VALUE | STATEMENT log_op STATEMENT | (STATEMENT) | !(STATEMENT)

       VALUE = [VALUE log_op VALUE]
              For list-based types: string list. Matches strictly.  The log_op must always be of one type  within  the
              whole list value.

       VALUE = {VALUE log_op VALUE}
              For  list-based  types: string list. Matches a subset.  The log_op must always be of one type within the
              whole list value.

       VALUE = value
              For scalar types: number (integer), size (floating point number with size unit suffix), percent  (float-
              ing point number with or without % suffix), string.

DIAGNOSTICS
       All tools return a status code of zero on success or non-zero on failure.

ENVIRONMENT VARIABLES
       HOME   Directory containing .lvm_history if the internal readline shell is invoked.

       LVM_COMMAND_PROFILE
              Name  of  default  command  profile  to use for LVM commands. This profile is overriden by direct use of
              --commandprofile command line option.

       LVM_SYSTEM_DIR
              Directory containing lvm.conf(5) and other LVM system files.  Defaults to "/etc/lvm".

       LVM_SUPPRESS_FD_WARNINGS
              Suppress warnings about unexpected file descriptors passed into LVM.

       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.

       LVM_LVMETAD_PIDFILE
              Path to the file that stores the lvmetad process ID.

       LVM_LVMETAD_SOCKET
              Path to the socket used to communicate with lvmetad.

       LVM_LVMPOLLD_PIDFILE
              Path to the file that stores the lvmpolld process ID.

       LVM_LVMPOLLD_SOCKET
              Path to the socket used to communicate with lvmpolld..

       LVM_LOG_FILE_EPOCH
              A  string  of  up to 32 letters appended to the log filename and followed by the process ID and a times-
              tamp.  When set, each process logs to a separate file.

       LVM_EXPECTED_EXIT_STATUS
              The status anticipated when the process exits.  Use ">N" to match any status greater  than  N.   If  the
              actual  exit  status  matches  and  a  log  file  got  produced,  it is deleted.  LVM_LOG_FILE_EPOCH and
              LVM_EXPECTED_EXIT_STATUS together allow automated test scripts to discard uninteresting log data.

       LVM_SUPPRESS_LOCKING_FAILURE_MESSAGES
              Used to suppress warning messages when the configured locking is known to be unavailable.

       DM_ABORT_ON_INTERNAL_ERRORS
              Abort processing if the code detects a non-fatal internal error.

       DM_DISABLE_UDEV
              Avoid interaction with udev.  LVM will manage the relevant nodes in /dev directly.

FILES
       /etc/lvm/lvm.conf
       $HOME/.lvm_history

SEE ALSO
       lvm.conf(5),  lvmcache(7),  lvmthin(7),   clvmd(8),   dmsetup(8),   lvchange(8),   lvcreate(8),   lvdisplay(8),
       lvextend(8),  lvmchange(8),  lvmconfig(8),  lvmdiskscan(8), lvreduce(8), lvremove(8), lvrename(8), lvresize(8),
       lvs(8), lvscan(8), pvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8), pvremove(8), pvs(8),  pvscan(8),
       vgcfgbackup(8),  vgchange(8),  vgck(8),  vgconvert(8),  vgcreate(8),  vgdisplay(8),  vgextend(8),  vgimport(8),
       vgimportclone(8),  vgmerge(8),  vgmknodes(8),  vgreduce(8),  vgremove(8),   vgrename(8),   vgs(8),   vgscan(8),
       vgsplit(8), readline(3)



Sistina Software UKLVM TOOLS 2.02.143(2)-RHEL6 (2016-12-13)             LVM(8)