Provided by: lvm2_2.03.27-1ubuntu1_amd64 
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 extents, 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 descriptions 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|json_std ]
[ --fs String ]
[ --fsmode String ]
[ 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 information 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 separated 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) devices/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 debugging.
-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
number 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 - prefix is used, the
value is not an absolute size, but is relative and added or subtracted from the current size.
-f|--force ...
Override various checks, confirmations and protections. Use with extreme caution.
--fs String
Control file system resizing when resizing an LV. checksize: Check the fs size and reduce the LV
if the fs is not using the reduced space (fs reduce is not needed.) If the reduced space is used
by the fs, then do not resize the fs or LV, and return an error. (checksize only applies when
reducing, and does nothing for extend.) resize: Resize the fs by calling the fs-specific resize
command. This may also include mounting, unmounting, or running fsck. See --fsmode to control
mounting behavior, and --nofsck to disable fsck. resize_fsadm: Use the old method of calling
fsadm to handle the fs (deprecated.) Warning: this option does not prevent lvreduce from
destroying file systems that are unmounted (or mounted if prompts are skipped.) ignore: Resize
the LV without checking for or handling a file system. Warning: using ignore when reducing the LV
size may destroy the file system.
--fsmode String
Control file system mounting behavior for fs resize. manage: Mount or unmount the fs as needed to
resize the fs, and attempt to restore the original mount state at the end. nochange: Do not mount
or unmount the fs. If mounting or unmounting is required to resize the fs, then do not resize the
fs or the LV and fail the command. offline: Unmount the fs if it is mounted, and resize the fs
while it is unmounted. If mounting is required to resize the fs, then do not resize the fs or the
LV and fail the command.
-h|--help
Display help text.
--journal String
Record information in the systemd journal. This information is in addition to information 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 information.
--longhelp
Display long help text.
-n|--nofsck
Do not perform fsck when resizing the file system with --resizefs.
--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 synchronization. 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|json_std
Overrides current output format for reports which is defined globally by the report/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. json_std produces report output in JSON format which is
more compliant with JSON standard. See lvmreport(7) for more information.
-r|--resizefs
Resize the fs using the fs-specific resize command. May include mounting, unmounting, or running
fsck. See --fsmode to control mounting behavior, and --nofsck to disable fsck. See --fs for more
options (--resizefs is equivalent to --fs resize.)
-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 reading 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 includes 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), lvmcache(7), lvmraid(7), lvmthin(7), lvmvdo(7), lvmautoactivation(7)