lvreduce(1M) lvreduce(1M)
NAME [Toc] [Back]
lvreduce - decrease space allocation or the number of mirror copies of
logical volumes
SYNOPSIS [Toc] [Back]
/usr/sbin/lvreduce [-A autobackup] [-f] -l le_number lv_path
/usr/sbin/lvreduce [-A autobackup] [-f] -L lv_size lv_path
/usr/sbin/lvreduce [-A autobackup] -m mirror_copies lv_path
[pv_path ...]
/usr/sbin/lvreduce [-A autobackup] -k -m mirror_copies lv_path
Remarks [Toc] [Back]
Mirrored disk operations require the installation of the optional HP
MirrorDisk/UX software, which is not included in the standard HP-UX
operating system.
lvreduce cannot be performed if the volume group is activated in shared
mode.
DESCRIPTION [Toc] [Back]
The lvreduce command reduces the number of logical extents allocated
to a logical volume specified by lv_path. The excess physical extents
in the logical volume and any mirror copies are deallocated.
Alternatively, it reduces the number of mirror copies in the logical
volume. The physical extents that comprise the deleted mirror copy or
copies are deallocated. If pv_path ... is specified, the mirror or
mirrors to be removed will be deallocated from those specific physical
volumes.
lvreduce asks for confirmation before deallocating logical extents if
the -f option is omitted.
Options and Arguments [Toc] [Back]
The -m option and pv_path argument are only meaningful if the optional
HP MirrorDisk/UX software has been installed on the system.
lvreduce recognizes the following options and arguments:
lv_path The block device path name of a logical
volume.
pv_path The block device path name of a physical
volume.
-A autobackup Set automatic backup for invocation of this
command. autobackup can have one of the
following values:
Hewlett-Packard Company - 1 - HP-UX 11i Version 2: August 2003
lvreduce(1M) lvreduce(1M)
y Automatically back up configuration
changes made to the logical volume.
This is the default.
After this command executes, the
vgcfgbackup command (see
vgcfgbackup(1M)) is executed for the
volume group to which the logical volume
belongs.
n Do not back up configuration changes.
-f Force reduction of the number of logical
extents without first requesting
confirmation.
This option can be dangerous when there is a
file system on the lv_path that is larger
than the size that the logical volume is
being reduced to. If the file system is
unmounted, the -f option forces the reduction
of the logical volume without reducing the
file system. The file system becomes corrupt
and is not mountable. If the file system is
mounted, lvreduce fails, preventing a mounted
file system from becoming corrupted.
-l le_number Decrease the space allocated to the logical
volume, specified in logical extents.
le_number is a decimal value smaller than the
current number of logical extents, in the
range 1 to 65535 (the implementation limit).
One, and only one, -l, -L, or -m option must
be supplied.
-L lv_size Decrease the space allocated to the logical
volume, specified in megabytes. lv_size is a
decimal value smaller than the current
logical volume size, in the range 1 to
16777216 (the implementation limit). lv_size
is rounded up to the nearest multiple of the
logical extent size, equivalent to the
physical extent size defined for the volume
group by the vgcreate command (see
vgcreate(1M)).
One, and only one, -l, -L, or -m option must
be specified.
Hewlett-Packard Company - 2 - HP-UX 11i Version 2: August 2003
lvreduce(1M) lvreduce(1M)
-m mirror_copies Reduce the number of mirror copies allocated
for each logical extent. A mirror copy
contains the same data as the original.
mirror_copies can have the value 0 or 1. It
must be smaller than the current value.
If optional pv_path arguments are specified,
the mirror copies are deallocated from the
specified physical volumes.
One, and only one, -l, -L, or -m option must
be specified.
-k This option should be used only in the
special instance when you want to reduce a
mirrored logical volume on a physical volume
that is missing or has failed.
Use this option with the -m option.
EXTERNAL INFLUENCES [Toc] [Back]
Environment Variables
LANG determines the language in which messages are displayed.
If LANG is not specified or is null, it defaults to "C" (see lang(5)).
If any internationalization variable contains an invalid setting, all
internationalization variables default to "C" (see environ(5)).
EXAMPLES [Toc] [Back]
Decrease the number of the logical extents of a logical volume to one
hundred:
lvreduce -l 100 /dev/vg01/lvol3
Reduce to one mirror (that is, an original and one copy) for each
logical extent of a logical volume:
lvreduce -m 1 /dev/vg01/lvol5
Remove mirror copies of logical extents of a logical volume from the
physical volume /dev/dsk/c1t0d0:
lvreduce -m 0 /dev/vg01/lvol4 /dev/dsk/c1t0d0
Remove a logical volume from a one-way mirrored set on the specified
pv_path.
lvreduce -m 0 -k /dev/vg01/lvol1 /dev/dsk/c1t0d0
Hewlett-Packard Company - 3 - HP-UX 11i Version 2: August 2003
lvreduce(1M) lvreduce(1M)
WARNINGS [Toc] [Back]
LVM does not store any information about which physical extents within
a logical volume contain useful data; therefore, reducing the space
allocated to a logical volume without doing a prior backup of the data
could lead to the loss of useful data. The lvreduce command on a
logical volume containing a file system of greater length than the
size being reduced to will cause data corruption.
To reduce a logical volume being used for swap, that swap area must
not be currently in use.
SEE ALSO [Toc] [Back]
lvcreate(1M), lvdisplay(1M), lvextend(1M), pvchange(1M),
pvdisplay(1M).
Hewlett-Packard Company - 4 - HP-UX 11i Version 2: August 2003 [ Back ] |
