.TH LVREDUCE 8 "LVM TOOLS #VERSION#" "Sistina Software UK" \" -*- nroff -*-
.SH NAME
lvreduce \- reduce the size of a logical volume
.SH SYNOPSIS
.B lvreduce
.RB [ \-A | \-\-autobackup
.RI { y | n }]
.RB [ \-\-commandprofile
.IR ProfileName ]
.RB [ \-d | \-\-debug ]
.RB [ \-h | \-\-help ]
.RB [ \-t | \-\-test ]
.RB [ \-v | \-\-verbose ]
.RB [ \-\-version ]
.RB [ \-f | \-\-force ]
.RB [ \-\-noudevsync ]
.RB { \-l | \-\-extents
.RI [ \- ] LogicalExtentsNumber [ % { VG | LV | FREE | ORIGIN "}] |"
.RB [ \-L | \-\-size
.RI [ \- ] LogicalVolumeSize [ bBsSkKmMgGtTpPeE ]}
.RB [ \-n | \-\-nofsck ]
.RB [ \-r | \-\-resizefs ]
.IR LogicalVolume { Name | Path }
.SH DESCRIPTION
lvreduce allows you to reduce the size of a logical volume.
Be careful when reducing a logical volume's size, because data in the
reduced part is lost!!!
.br
You should therefore ensure that any filesystem on the volume is
resized
.I before
running lvreduce so that the extents that are to be removed are not in use.
.br
Shrinking snapshot logical volumes (see
.BR lvcreate (8)
for information to create snapshots) is supported as well.
But to change the number of copies in a mirrored logical
volume use
.BR lvconvert (8).
.br
Sizes will be rounded if necessary - for example, the volume size must
be an exact number of extents and the size of a striped segment must
be a multiple of the number of stripes.
.br
.SH OPTIONS
See \fBlvm\fP(8) for common options.
.TP
.BR \-f ", " \-\-force
Force size reduction without prompting even when it may cause data loss.
.TP
.IR \fB\-l ", " \fB\-\-extents " [" \- ] LogicalExtentsNumber [ % { VG | LV | FREE | ORIGIN }]
Reduce or set the logical volume size in units of logical extents.
With the \fI-\fP sign the value will be subtracted from
the logical volume's actual size and without it the value will be taken
as an absolute size.
The total number of physical extents freed will be greater than this logical
value if, for example, the volume is mirrored.
The number can also be expressed as a percentage of the total space
in the Volume Group with the suffix \fI%VG\fP, relative to the existing
size of the Logical Volume with the suffix \fI%LV\fP, as a percentage of the
remaining free space in the Volume Group with the suffix \fI%FREE\fP, or (for
a snapshot) as a percentage of the total space in the Origin Logical
Volume with the suffix \fI%ORIGIN\fP.
The resulting value for the subtraction is rounded downward, for the absolute
size it is rounded upward.
N.B. In a future release, when expressed as a percentage with VG or FREE, the
number will be treated as an approximate total number of physical extents to be
freed (including extents used by any mirrors, for example).  The code may
currently release more space than you might otherwise expect.
.TP
.IR \fB\-L ", " \fB\-\-size " [" \- ] LogicalVolumeSize [ bBsSkKmMgGtTpPeE ]
Reduce or set the logical volume size in units of megabytes.
A size suffix of \fIk\fP for kilobyte, \fIm\fP for megabyte,
\fIg\fP for gigabytes, \fIt\fP for terabytes, \fIp\fP for petabytes
or \fIe\fP for exabytes is optional.
With the \fI\-\fP sign the value will be subtracted from
the logical volume's actual size and without it it will be taken as
an absolute size.
.TP
.BR \-n ", " \-\-nofsck
Do not perform fsck before resizing filesystem when filesystem
requires it. You may need to use \fB\-\-force\fR to proceed with
this option.
.TP
.BR \-\-noudevsync
Disable udev synchronisation. The
process will not wait for notification from udev.
It will continue irrespective of any possible udev processing
in the background.  You should only use this if udev is not running
or has rules that ignore the devices LVM2 creates.
.TP
.BR \-r ", " \-\-resizefs
Resize underlying filesystem together with the logical volume using
.BR fsadm (8).
.SH Examples
Reduce the size of logical volume lvol1 in volume group vg00 by 3 logical extents:
.sp
.B lvreduce \-l \-3 vg00/lvol1
.SH SEE ALSO
.BR fsadm (8),
.BR lvchange (8),
.BR lvconvert (8),
.BR lvcreate (8),
.BR lvextend (8),
.BR lvm (8),
.BR lvresize (8),
.BR vgreduce (8)