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LVM(8)                               System Manager's Manual                               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 com‐
       mand in detail.

       If lvm is invoked with no arguments it presents a readline prompt (assuming  it  was  com‐
       piled  with  readline  support).  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 warn‐
       ing about the leak.  This warning can be suppressed 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 commands.

       A  file containing a simple script with one command per line can also be given on the com‐
       mand 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 gener‐
       ically 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 sup‐
              press 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 dis‐
              abling all metadata writing but nevertheless returning success to the calling func‐
              tion.   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.

       --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  available  (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 Vol‐
              ume 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 otherwise. 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 selection
              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 with‐
              out 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-map‐
              per kernel driver, so this option is unable to report whether or not  Logical  Vol‐
              umes 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  lvm‐
              lockd  is  not  being used.  It can be used to report or display a lockd VG without
              locking.

       --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 multi‐
              ple  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 mul‐
              tiple 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 pol‐
              icy  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 con‐
              tiguous policy requires that new Physical Extents be placed  adjacent  to  existing
              Physical  Extents.  The cling policy places new Physical Extents on the same Physi‐
              cal 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, anywhere will - even if that reduces performance by  plac‐
              ing 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 methods. Using --commandprofile option over‐
              rides any command profile specified via LVM_COMMAND_PROFILE environment 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  Vol‐
              ume  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
              information  about  metadata profile config and the way it fits with other LVM con‐
              figuration 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 excep‐
              tion 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 existing configuration. The ConfigurationString is of  exactly  the
              same  format as used in any LVM configuration file. See lvm.conf(5) for more infor‐
              mation 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  con‐
       tain  any  of  the following strings: 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 distributions.  Other software and scripts
       should use the /dev/VolumeGroupName/LogicalVolumeName format to reduce the chance of need‐
       ing  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  inter‐
       nal layer names.

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 (contigu‐
       ous) 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 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 indepen‐
       dently 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  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_sepa‐
       rate_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  con‐
       siders  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 lay‐
       out  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 logi‐
       cal 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 consists 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  -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 suf‐
              fix), percent (floating 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 timestamp.  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 auto‐
              mated 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 UK             LVM TOOLS 2.02.133(2) (2015-10-30)                         LVM(8)

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