man > LVREDUCE

LVREDUCE(8)                            System Manager's Manual                           LVREDUCE(8)

NAME
       lvreduce — Reduce the size of a logical volume

SYNOPSIS
       lvreduce option_args position_args
           [ option_args ]

DESCRIPTION
       lvreduce  reduces  the  size of an LV. The freed logical extents are returned to the VG to be
       used by other LVs. A copy-on-write snapshot LV can also be reduced if less space is needed to
       hold COW blocks. Use lvconvert(8) to change the number of data images in a RAID  or  mirrored
       LV.

       Be  careful when reducing an LV's size, because data in the reduced area is lost. Ensure that
       any file system on the LV is resized before running lvreduce so that the removed extents  are
       not in use by the file system.

       Sizes  will  be rounded if necessary. For example, the LV size must be an exact number of ex‐
       tents, and the size of a striped segment must be a multiple of the number of stripes.

       In the usage section below, --size Size can be replaced with --extents Number.  See both  de‐
       scriptions the options section.

USAGE
       lvreduce -L|--size [-]Size[m|UNIT] LV
           [ -l|--extents [-]Number[PERCENT] ]
           [ -A|--autobackup y|n ]
           [ -f|--force ]
           [ -n|--nofsck ]
           [ -r|--resizefs ]
           [    --noudevsync ]
           [    --reportformat basic|json ]
           [ COMMON_OPTIONS ]

       Common options for lvm:
           [ -d|--debug ]
           [ -h|--help ]
           [ -q|--quiet ]
           [ -t|--test ]
           [ -v|--verbose ]
           [ -y|--yes ]
           [    --commandprofile String ]
           [    --config String ]
           [    --devices PV ]
           [    --devicesfile String ]
           [    --driverloaded y|n ]
           [    --journal String ]
           [    --lockopt String ]
           [    --longhelp ]
           [    --nohints ]
           [    --nolocking ]
           [    --profile String ]
           [    --version ]

OPTIONS


       -A|--autobackup y|n
              Specifies if metadata should be backed up automatically after a change.  Enabling this
              is strongly advised! See vgcfgbackup(8) for more information.

       --commandprofile String
              The command profile to use for command configuration.  See lvm.conf(5) for more infor‐
              mation about profiles.

       --config String
              Config  settings for the command. These override lvm.conf(5) settings.  The String arg
              uses the same format as lvm.conf(5), or may use section/field syntax.  See lvm.conf(5)
              for more information about config.

       -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).

       --devices PV
              Restricts  the  devices  that  are visible and accessible to the command.  Devices not
              listed will appear to be missing. This option can be repeated, or accepts a comma sep‐
              arated list of devices. This overrides the devices file.

       --devicesfile String
              A file listing devices that LVM should use.  The file must exist in  /etc/lvm/devices/
              and  is  managed  with  the lvmdevices(8) command.  This overrides the lvm.conf(5) de‐
              vices/devicesfile and devices/use_devicesfile settings.

       --driverloaded y|n
              If set to no, the command will not attempt to use device-mapper.  For testing and  de‐
              bugging.

       -l|--extents [-]Number[PERCENT]
              Specifies the new size of the LV in logical extents.  The --size and --extents options
              are  alternate  methods of specifying size.  The total number of physical extents used
              will be greater when redundant data is needed for RAID levels.   An  alternate  syntax
              allows  the  size to be determined indirectly as a percentage of the size of a related
              VG, LV, or set of PVs. The suffix %VG denotes the total size of  the  VG,  the  suffix
              %FREE  the  remaining  free space in the VG, and the suffix %PVS the free space in the
              specified PVs.  For a snapshot, the size can be expressed as a percentage of the total
              size of the origin LV with the suffix %ORIGIN (100%ORIGIN provides space for the whole
              origin).  When expressed as a percentage, the size defines an upper limit for the num‐
              ber of logical extents in the new LV. The precise number of logical extents in the new
              LV is not determined until the command has completed.  When the plus + or minus - pre‐
              fix is used, the value is not an absolute size, but is  relative  and  added  or  sub‐
              tracted from the current size.

       -f|--force ...
              Override various checks, confirmations and protections.  Use with extreme caution.

       -h|--help
              Display help text.

       --journal String
              Record  information in the systemd journal.  This information is in addition to infor‐
              mation enabled by the lvm.conf log/journal setting.  command: record information about
              the command.  output: record the default command output.  debug: record  full  command
              debugging.

       --lockopt String
              Used to pass options for special cases to lvmlockd.  See lvmlockd(8) for more informa‐
              tion.

       --longhelp
              Display long help text.

       -n|--nofsck
              Do  not  perform  fsck before resizing filesystem when filesystem requires it. You may
              need to use --force to proceed with this option.

       --nohints
              Do not use the hints file to locate devices for PVs. A command may read  more  devices
              to find PVs when hints are not used. The command will still perform standard hint file
              invalidation where appropriate.

       --nolocking
              Disable  locking. Use with caution, concurrent commands may produce incorrect results.


       --noudevsync
              Disables udev synchronisation. The process will not wait for notification  from  udev.
              It  will continue irrespective of any possible udev processing in the background. Only
              use this if udev is not running or has rules that ignore the devices LVM creates.

       --profile String
              An alias for --commandprofile or --metadataprofile, depending on the command.

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

       --reportformat basic|json
              Overrides  current  output  format  for  reports  which is defined globally by the re‐
              port/output_format setting in lvm.conf(5).  basic is the original format with  columns
              and  rows.  If there is more than one report per command, each report is prefixed with
              the report name for identification. json produces report output in  JSON  format.  See
              lvmreport(7) for more information.

       -r|--resizefs
              Resize underlying filesystem together with the LV using fsadm(8).

       -L|--size [-]Size[m|UNIT]
              Specifies  the  new  size  of  the LV.  The --size and --extents options are alternate
              methods of specifying size.  The total number of physical extents used will be greater
              when redundant data is needed for RAID levels.  When the plus + or minus -  prefix  is
              used,  the value is not an absolute size, but is relative and added or subtracted from
              the current size.

       -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 read‐
              ing back metadata it believes has changed but hasn't.

       -v|--verbose ...
              Set verbose level. Repeat from 1 to 4 times to increase the detail of messages sent to
              stdout and stderr.

       --version
              Display version information.

       -y|--yes
              Do  not  prompt  for  confirmation interactively but always assume the answer yes. Use
              with extreme caution.  (For automatic no, see -qq.)

VARIABLES
       LV     Logical Volume name.  See lvm(8) for valid names.  An LV positional arg generally  in‐
              cludes the VG name and LV name, e.g. VG/LV.

       String See the option description for information about the string content.

       Size[UNIT]
              Size is an input number that accepts an optional unit.  Input units are always treated
              as base two values, regardless of capitalization, e.g. 'k' and 'K' both refer to 1024.
              The  default  input  unit  is specified by letter, followed by |UNIT.  UNIT represents
              other possible input units: b|B is bytes, s|S is sectors of 512 bytes, k|K is KiB, m|M
              is MiB, g|G is GiB, t|T is TiB, p|P is PiB, e|E is EiB.  (This should not be  confused
              with the output control --units, where capital letters mean multiple of 1000.)

ENVIRONMENT VARIABLES
       See lvm(8) for information about environment variables used by lvm.  For example, LVM_VG_NAME
       can generally be substituted for a required VG parameter.

EXAMPLES
       Reduce the size of an LV by 3 logical extents:
       lvreduce -l -3 vg00/lvol1

SEE ALSO
       lvm(8), lvm.conf(5), lvmconfig(8), lvmdevices(8),

       pvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8), pvremove(8), pvresize(8), pvs(8),
       pvscan(8),

       vgcfgbackup(8), vgcfgrestore(8), vgchange(8), vgck(8), vgcreate(8), vgconvert(8),
       vgdisplay(8), vgexport(8), vgextend(8), vgimport(8), vgimportclone(8), vgimportdevices(8),
       vgmerge(8), vgmknodes(8), vgreduce(8), vgremove(8), vgrename(8), vgs(8), vgscan(8),
       vgsplit(8),

       lvcreate(8), lvchange(8), lvconvert(8), lvdisplay(8), lvextend(8), lvreduce(8), lvremove(8),
       lvrename(8), lvresize(8), lvs(8), lvscan(8),

       lvm-fullreport(8), lvm-lvpoll(8), blkdeactivate(8), lvmdump(8),

       dmeventd(8), lvmpolld(8), lvmlockd(8), lvmlockctl(8), cmirrord(8), lvmdbusd(8), fsadm(8),

       lvmsystemid(7), lvmreport(7), lvmraid(7), lvmthin(7), lvmcache(7)

Red Hat, Inc.                     LVM TOOLS 2.03.16(2) (2022-05-18)                      LVREDUCE(8)