LVM Volume Group Dynamic LUN Expansion (DLE) and Contraction (DLC) (September 2009)

vgmodify for Version 2.0 volume groups

This section describes how to use the vgmodify command to perform online dynamic LUN expansion

(DLE), online dynamic LUN contraction (DLC), and online volume group reprovisioning (changing

maximum VG size) for Version 2.x volume groups.

The vgmodify command for Version 2.x volume groups is available in the HP-UX 11i v3 March

2009 Update. For information on using vgmodify on Version 1.0 volume groups, see the vgmodify for

Versi

on 1.0 volume groups section.

Command differences between Version 1.0 and 2.x volume groups

For Version 2.x volume groups, the vgmodify command has the following differences from the

vgmodify command for Version 1.0 volume groups:

• Modes

It is only supported for activated volume groups (online mode). For Version 1.0 volume

groups, the vgmodify command has an offline mode and an online mode.

• Options

Has a –S option to select the maximum volume group size (for reprovisioning) that is not

available for Version 1.0 volume groups. The following options available for Version 1.0

volume groups are not applicable for Version 2.x volume groups: –e (for max PEs per PV), -

p (for max PVs), –l (for max LVs), and –t (table mode). For a complete list of Version 1.0

and 2.x options, see vgmodify(1M).

• Operation

The vgmodify command for Version 1.0 volume groups suspends the volume group in

certain cases and performs the reconfiguration using vgcfgrestore. The vgmodify

command for Version 2.x does not suspend the volume group and modifies the on-disk

configuration data without requiring a vgcfgbackup file.

• Output messages

The vgmodify output messages for Versions 1.0 volume groups are different from the output

messages for Version 2.x volume groups.

Command similarities between Version 1.0 and 2.x volume groups

The vgmodify command options for online DLE and online DLC are the same for Version 1.0 and

Version 2.x volume groups. For online DLE, the –a and –E options are required. Online DLE can

target a single PV, all PVs in the VG, or selected PVs. For online DLC, the –a and –C options are

required. Online DLC requires a DLC_size parameter, and must target a single PV.

The –r option is the review mode option for both versions. Without the –r option (and without the –t

option in Version 1.0), vgmodify runs in change mode, in which it attempts to reconfigure the

volume group.

Command line options

The vgmodify command for Version 2.x volume groups supports the following tasks and command

line syntaxes:

• Reconfigure physical volumes for dynamic LUN expansion (DLE)

vgmodify -a –E [-r] VolumeGroupName [pv_path ...]

• Reconfigure a physical volume for dynamic LUN contraction (DLC)