lvsplit(1M) lvsplit(1M)
Requires Optional HP MirrorDisk/UX Software
NAME [Toc] [Back]
lvsplit - split mirrored LVM logical volume into two logical volumes
SYNOPSIS [Toc] [Back]
/usr/sbin/lvsplit [-A autobackup] [-s suffix] [-g PhysicalVolumeGroup]
lv_path ...
Remarks [Toc] [Back]
This command requires the installation of the optional HP MirrorDisk/UX
software (not included in the standard HP-UX operating system) before
it can be used.
lvsplit cannot be performed if the volume group is activated in shared
mode.
DESCRIPTION [Toc] [Back]
The lvsplit command splits a single- or double-mirrored logical
volume, lv_path, into two logical volumes. A second logical volume is
created containing one copy of the data. The original logical volume
is appropriately reset as unmirrored or single-mirrored.
If the -s option is specified, the new logical volume name has the
form lv_pathsuffix. If -s is not specified, suffix defaults to b, as
in lv_pathb.
If more than one lv_path is specified on the command line, lvsplit
ensures that all logical volumes are brought offline together in one
system call, ensuring predictable results among the logical volumes.
Up to 127 logical volumes can be specified on the command line. All
logical volumes must belong to the same volume group, and there must
be enough unused logical volumes remaining in the volume group to hold
the newly split logical volumes. A volume group can contain up to 255
logical volumes.
If PhysicalVolumeGroup is specified, the offline logical volumes are
created using the mirror copies on the physical volumes contained in
the specified physical volume group.
Whenever a mirrored logical volume is split into two logical volumes,
a bit map 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 bit map is used to decide which
areas of the logical volumes need to be resynchronized (see
lvmerge(1M)). This bit map remains in existence until the merge is
completed, until one of the logical volumes is extended, reduced, or
split again, or until the system is rebooted.
The new logical volume must be checked with the fsck command before it
is mounted (see fsck(1M)). lvsplit flushes the file system to a
consistent state except for pipes and unlinked but open files.
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lvsplit(1M) lvsplit(1M)
Requires Optional HP MirrorDisk/UX Software
To rejoin two split copies of a logical volume, use the lvmerge
command (see lvmerge(1M)).
Options and Arguments [Toc] [Back]
lvsplit recognizes the following options and arguments:
lv_path The block device path name of a logical
volume. Up to 127 logical volumes in the
same volume group can be specified at one
time.
-A autobackup Set automatic backup for 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.
-g PhysicalVolumeGroup
The offline logical volumes will be created
using the mirror copies on the physical
volumes in the specified PhysicalVolumeGroup.
-s suffix Specify the suffix to use to identify the new
logical volume. The new logical volume name
has the form lv_pathsuffix. If -s is
omitted, suffix defaults to b, as in
lv_pathb.
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]
Split the mirrored logical volume /dev/vg00/lvol1 into two copies.
Call the new logical volume /dev/vg00/lvol1backup:
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lvsplit(1M) lvsplit(1M)
Requires Optional HP MirrorDisk/UX Software
lvsplit -s backup /dev/vg00/lvol1
Split the mirrored logical volume /dev/vg00/lvol1 into two copies.
The offline logical volume will be created using the mirror copy on
the physical volumes contain in the physical volume group pvg1.
lvsplit -g pvg1 /dev/vg00/lvol1
Split an online logical volume which is currently mounted on /usr so
that a backup can take place:
lvsplit /dev/vg00/lvol1
fsck /dev/vg00/lvol1b
mount /dev/vg00/lvol1b /usr.backup
Perform a backup operation, then:
umount /usr.backup
lvmerge /dev/vg00/lvol1b /dev/vg00/lvol1
Split two logical volumes at the same time:
lvsplit /dev/vg01/database1 /dev/vg01/database2
Perform operation on split logical volumes, then rejoin them:
lvmerge /dev/vg01/database1b /dev/vg01/database1
lvmerge /dev/vg01/database2b /dev/vg01/database1
WARNINGS [Toc] [Back]
After a two-way mirrored logical volume has been split once, it cannot
be split again without merging the logical volumes using the lvmerge
command (see lvmerge(1M)).
SEE ALSO [Toc] [Back]
lvcreate(1M), lvextend(1M), lvmerge(1M).
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