NAME

lvmerge − merge two logical volumes into one logical volume

SYNOPSIS

/etc/lvmerge backup_lv_path master_lv_path

Remarks:

This command requires installation of optional LVM MIRRORING software (not included in the standard HP-UX operating system) before it can be used. 

DESCRIPTION

lvmerge merges two Logical Volumes of the same size, increasing the number of mirrored copies of the master_lv_path by the number of copies in the backup_lv_path.

Data previously contained in the backup_lv_path is resynchronized using the data in the master_lv_path. All new data on the backup_lv_path is lost. 

Whenever a mirrored logical volume is split into two logical volumes, 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 the logical volumes need to be resynchronized.  This bitmap continues to exist until the merge is completed, or until either of the logical volumes is extended or reduced, or the system is rebooted. 

If there is no bitmap available, the entire logical volume is resynchronized. 

The normal usage for this command is to merge previously mirrored logical volumes that have been split using the lvsplit command (see lvsplit(1M). However, the two logical volumes are not required to have been the result of a previous lvsplit operation. 

EXTERNAL INFLUENCES

Environment Variables

LANG determines the language in which messages are displayed. 

If LANG is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of LANG. 

If any internationalization variable contains an invalid setting, lvmerge behaves as if all internationalization variables are set to "C".  See environ(5).

EXAMPLES

Merge /dev/vg00/lvol1b with /dev/vg00/lvol1:

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

WARNINGS

All data on backup_lv_path is lost after the merge if no bitmap is found. 

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

SEE ALSO

lvsplit(1M), lvcreate(1M), lvextend(1M). 

Hewlett-Packard Company  —  HP-UX Release 9.10: April 1995