HP-UX Reference (11i v1 05/09) - 1M System Administration Commands A-M (vol 3)

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lvcreate(1M) lvcreate(1M)

g Set a PVG-strict allocation policy. Mirrors of a logical extent cannot share

the same physical volume group. A PVG-strict allocation policy cannot be set

on a logical volume in a volume group that does not have a physical volume

group deﬁned.

n Do not set a strict or PVG-strict allocation policy. Mirrors of a logical extent

can share the same physical volume.

Striped logical volumes are only allocated using the strict or PVG-strict allocation policies. The number of

extents for a striped logical volume is always a multiple of the number of disks the logical volume is striped

across. A logical volume striped across n disks, is allocated in sets of n extents, and each extent of a given

set is allocated on a different physical volumes in the volume group.

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

Create a logical volume in volume group

/dev/vg02:

lvcreate /dev/vg02

Create a logical volume in volume group /dev/vg03 with nonstrict allocation policy:

lvcreate -s n /dev/vg03

Create a logical volume of size 100 MB in volume group /dev/vg03 :

lvcreate -L 100 /dev/vg03

Create a logical volume of size 90 MB striped across 3 disks with a stripe size of 64 KB:

lvcreate -L 90 -i 3 -I 64 /dev/vg03

Distributed Allocation Policy

This example shows how the -D y option can be used to create EXTENT-BASED MIRRORED STRIPES.

Assume that volume group /dev/vgtest has two physical volume groups: pvg1, pvg2.

Assume that each physical volume group has 2 physical volumes.

Assume that the ﬁrst physical volume in each pvg has 3 extents free and the second physical volume in

each pvg has 2 extents free.

The following command creates a logical volume in vgtest with EXTENT-BASED MIRRORED STRIPES:

lvcreate -D y -s g -m 1 -l 5 /dev/vgtest

The distributed allocation proceeds as follows:

• A free extent is allocated from the 1st pvol in pvg1.

• A free extent is allocated from the 2nd pvol in pvg1.

• A free extent is allocated from the 1st pvol in pvg1.

• A free extent is allocated from the 2nd pvol in pvg1.

• A free extent is allocated from the 1st pvol in pvg1.

• Mirrors for the ﬁve extents are then allocated from the free extents in pvg2 in a similar manner.

WARNINGS

The root, swap, and dump logical volumes (see lvlnboot(1M)) must be created with contiguous allocation

policy.