lvmerge(1M)

NAME

lvmerge — merge two LVM logical volumes into one logical volume

SYNOPSIS

/usr/sbin/lvmerge [-A autobackup] copy_lv_path master_lv_path

Remarks

This command requires the installation of the optional HP MirrorDisk/UX software, which is not included in the standard HP-UX operating system.

lvmerge cannot be performed if the volume group is activated in shared mode.

DESCRIPTION

The lvmerge command merges two logical volumes of the same size. The copy_lv_path is added as a mirrored copy of master_lv_path and only the master_lv_path logical volume is retained. The number of mirrored copies of the master_lv_path is increased by the number of copies in the copy_lv_path.

Data previously contained in the copy_lv_path will be resynchronized using the data in the master_lv_path. All new data on the copy_lv_path will be destroyed and the copy_lv_path logical volume will be removed. lvmerge blocks until all the extents are resynchronized.

The normal usage for this command is to merge previously mirrored logical volumes that have been split using the lvsplit command. However, the two logical volumes are not required to have been the result of a previous lvsplit operation.

NOTE: Whenever a mirrored logical volume is split into two logical volumes using lvsplit, a bitmap is stored that keeps track of all writes to either logical volume in the split pair. When the two logical volumes are subsequently merged using lvmerge, the bitmap is used to decide which areas of copy_lv_path need to be resynchronized with the master_lv_path. This bitmap remains in existence until one of the following conditions occurs:

The merge is completed.
One of the logical volumes is extended, reduced, or split again.
The volume group is deactivated, or cross-activated to shared mode (see vgchange(1M)).
The system is rebooted.

If there is no bitmap available, all the physical extents from the copy_lv_path are marked stale.

Options and Arguments

lvmerge recognizes the following options and arguments:

copy_lv_path

The block device path name of a logical volume that will be removed.

master_lv_path

The block device path name of a logical volume that will remain.

-A autobackup

Set automatic backup for this invocation of this command. autobackup can have one of the following values:

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 this time.

EXTERNAL INFLUENCES

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

Merge /dev/vg00/lvol1b with /dev/vg00/lvol1. Data in /dev/vg00/lvol1b will be overwritten by /dev/vg00/lvol1 and /dev/vg00/lvol1b will be removed.

lvmerge /dev/vg00/lvol1b /dev/vg00/lvol1 

WARNINGS

lvmerge does not check to guarantee that the allocation policy of master_lv_path is preserved after the merge.