HP-UX Reference (11i v2 03/08) - 1M System Administration Commands A-M (vol 3)

l
lvcreate(1M) lvcreate(1M)
-s strict Set the strict allocation policy. Mirror copies of a logical extent can be
allocated to share or not share the same physical volume or physical
volume group. strict can have one of the following values:
y Set a strict allocation policy. Mirrors of a logical extent cannot
share the same physical volume. This is the default.
g Set a PVG-strict allocation policy. Mirrors of a logical extent can-
not 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 logi-
cal 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.
Section 1M−−392 Hewlett-Packard Company − 4 − HP-UX 11i Version 2: August 2003