Importing A Volume Group; Modifying Volume Group Parameters - HP -UX 11i Administrator's Manual

When vgexport completes, all information about the volume group has been removed from the
system. The disks can now be moved to a different system, and the volume group can be imported
there.

Importing a Volume Group

To import a volume group, follow these steps:
1. Connect the disks to the system.
2. If you are using an HP-UX release before March 2008, or if you want to specify the minor
number of the volume group device file, create it using the procedure in
Group Device File" (page
3. Use the vgimport command to import the volume group:
# vgimport -v -N -m /tmp/vgnn.map /dev/vgnn list_of_disks
If there are several disks in the volume group and the VGID was saved in the mapfile (that is,
the vgexport command was run with the s and m options), you can avoid specifying all
of them in the vgimport command line by using the -s option. This causes vgimport to
scan all the disks on the system. Any physical volumes with a VGID matching the one in the
mapfile are included automatically into the volume group.
4. Activate the volume group as follows:
# vgchange -a y vgnn
NOTE: If the volume group contains any multipathed disks, HP recommends using HP-UX's native
multipathing that is a superset of LVM's alternate links. See
Through Multipathing" (page 28)
If you want to use LVM's alternate link features, importing the volume group has several implications:
You must omit the -N option to the vgimport command.
The vgimport sets the first link found as the primary link for all physical volumes. If the links
are not in the desired order after the import, use vgreduce and vgextend on the primary
link for each physical volume for which you want to change the primary.
The tunable maxfiles must be more than double the number of disks free.

Modifying Volume Group Parameters

When you create a volume group, you set certain characteristics of the volume group. Using the
vgmodify command you can adjust some of the volume group parameters without removing and
re-creating the volume group or having to move your data. The vgmodify command enables you
to alter different parameters for Version 1.0 volume groups and Version 2.x volume groups.
For version 1.0 volume groups, you can use vgmodify to do the following:
Detect and handle physical volume size changes.
Modify the maximum number of physical extents that can be allocated per physical volume.
Modify the maximum number of physical volumes that the volume group can contain.
Modify the maximum number of logical volumes that the volume group can contain.
Change a disk type from boot to non-boot or vice versa.
Handle physical volume LUN expansion. See
(page 77)
Prepare a physical volume for a LUN contraction. See
Characteristics" (page 77)
58 Administering LVM
44).
for more information.
for more details
for more details.
"Increasing Hardware Path Redundancy
"Modifying Physical Volume Characteristics"
"Modifying Physical Volume
"Creating the Volume