table of contents
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 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
[ -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:
[ -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)
LVM TOOLS 2.03.23(2) (2023-11-21) | Red Hat, Inc. |