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 run-
ning 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 ]
[ 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) set-
tings. The String arg uses the same format as lvm.conf(5), or
may use section/field syntax. See lvm.conf(5) for more informa-
tion 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) com-
mand. 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.
-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. out-
put: record the default command output. debug: record full com-
mand debugging.
--lockopt String
Used to pass options for special cases to lvmlockd. See lvm-
lockd(8) for more information.
--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.
--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 --ver-
bose. 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 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. 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 - pre-
fix 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 posi-
tional arg generally includes the VG name and LV name, e.g.
VG/LV.
String See the option description for information about the string con-
tent.
Size[UNIT]
Size is an input number that accepts an optional unit. Input
units are always treated as base two values, regardless of capi-
talization, e.g. 'k' and 'K' both refer to 1024. The default
input unit is specified by letter, followed by |UNIT. UNIT rep-
resents 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), lvm2-activation-generator(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 2.03.14(2)-RHEL8 (2021-10-20) LVREDUCE(8)
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