Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
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 command in detail.

       If lvm is invoked with no arguments it presents a readline prompt  (as-
       suming it was compiled with readline support).  LVM commands may	be en-
       tered 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  com-
       mand  (for  example  by using a hard or soft link) it acts as that com-
       mand.

       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	 suppressed  by	 setting  the  environment  variable  LVM_SUP-
       PRESS_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  substi-
       tuted.	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	infor-
       mation gets cached internally between commands.

       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.

       dumpconfig -- Display the configuration information after
	      loading lvm.conf(5) and any other	configuration files.

       devtypes	-- Display the recognised built-in block device	types.

       formats -- Display recognised metadata formats.

       help -- Display the help	text.

       pvdata -- Not implemented in LVM2.

       segtypes	-- Display recognised Logical Volume segment types.

       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	Physi-
	      cal Volumes.

       lvchange	-- Change attributes of	a Logical Volume.

       lvconvert  --  Convert  a Logical Volume	from linear to mirror or snap-
       shot.

       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.

       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 in-
       dividual	manual pages.

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

       --version
	      Display version information.

       -v, --verbose
	      Set  verbose level. Repeat from 1	to 3 times to increase the de-
	      tail 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 un-
	      usual 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 af-
	      ter 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 Vol-
	      ume Groups that are only partially available (one	or more	Physi-
	      cal  Volumes  belonging to the Volume Group are missing from the
	      system).	Where part of a	logical	volume is missing,  /dev/ioer-
	      ror  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 orig-
	      inal 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.   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  de-
	      fault (lvm2) can be changed by setting format in the global sec-
	      tion of the config file.

       --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	direc-
	      tory 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 clus-
	      tered 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.

       --addtag	Tag
	      Add  the tag Tag to a PV,	VG or LV.  Supply this argument	multi-
	      ple 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 to-
	      gether.  Tags can	be given on the	command	line in	place  of  PV,
	      VG or LV arguments.  Tags	should be prefixed with	@ to avoid am-
	      biguity.	Each tag is expanded by	replacing it with all  objects
	      possessing  that tag which are of	the type expected by its posi-
	      tion 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 al-
	      lowed 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 Vol-
	      ume.  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  ad-
	      jacent  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 alloca-
	      tion  request  but normal	doesn't	use them, anywhere 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 con-
	      figuration methods.

       --metadataprofile ProfileName
	      Selects the metadata configuration profile to use	when  process-
	      ing  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  ap-
	      plied  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	configuration methods.

       --profile ProfileName
	      A	 short	form  of  --metadataprofile  for  vgcreate,  lvcreate,
	      vgchange and lvchange command and	a short	form of	 --commandpro-
	      file  for	 any  other  command (with the exception of dumpconfig
	      command where the	--profile has special meaning, see  lvm	 dump-
	      config(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  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 re-
       served 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',  '_rlog',	 '_tdata'   or
       '_tmeta'.  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 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.

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 Ex-
       tents within those ranges on the	specified Physical Volumes are consid-
       ered.

       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 Logi-
       cal 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  ac-
       cording	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  configura-
       tion  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.

       Normal  will not	choose a Physical Extent that shares the same Physical
       Volume as a Logical Extent already allocated to a parallel Logical Vol-
       ume  (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	Physi-
       cal 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  al-
       location/thin_pool_metadata_require_separate_pvs	 configuration parame-
       ter.

       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 Vol-
       umes 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 pro-
       visioning (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 <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

       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. 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 (floating	point number  with  or
	      without %	suffix), string.

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

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

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

       LVM_SUPPRESS_FD_WARNINGS
	      Suppress warnings	about openned file descriptors,	when lvm  com-
	      mand is executed.

       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 for the lvmetad pid file.

       LVM_LVMETAD_SOCKET
	      Path for the lvmetad socket file.

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

SEE ALSO
       lvm.conf(5), lvmcache(7), lvmthin(7), lvm dumpconfig(8),	clvmd(8),  dm-
       setup(8),  lvchange(8),	lvcreate(8),  lvdisplay(8),  lvextend(8), lvm-
       change(8), lvmdiskscan(8), lvreduce(8), lvremove(8), lvrename(8), lvre-
       size(8),	 lvs(8),  lvscan(8), pvchange(8), pvck(8), pvcreate(8),	pvdis-
       play(8),	pvmove(8),  pvremove(8),  pvs(8),  pvscan(8),  vgcfgbackup(8),
       vgchange(8),  vgck(8),  vgconvert(8),  vgcreate(8), vgdisplay(8), vgex-
       tend(8),	vgimport(8), vgimportclone(8), vgmerge(8), vgmknodes(8), vgre-
       duce(8),	vgremove(8), vgrename(8), vgs(8), vgscan(8), vgsplit(8), read-
       line(3)

Sistina	Software UKLVM TOOLS 2.02.115(2)-RHEL7 (2015-01-28)		LVM(8)

NAME | SYNOPSIS | DESCRIPTION | BUILT-IN COMMANDS | COMMANDS | OPTIONS | VALID NAMES | ALLOCATION | LOGICAL VOLUME TYPES | SELECTION CRITERIA | DIAGNOSTICS | ENVIRONMENT VARIABLES | FILES | SEE ALSO

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=lvm&sektion=8&manpath=CentOS+7.1>

home | help