extendlv

extendlv Command



Purpose

Increases the size of a logical volume by adding unallocated physical
partitions from within the volume group.

Syntax



To Add Available Physical Partitions

extendlv [ -a Position ] [ -e Range ] [ -u Upperbound ] [ -s
Strict ] LogicalVolume Partitions [ PhysicalVolume ... ]

To Add Specific Physical Partitions

extendlv [ -m MapFile ] LogicalVolume Partitions

Description

Attention: This command is not allowed if the volume group is varied
on in concurrent mode.

The extendlv command increases the number of logical partitions allocated
to the LogicalVolume by allocating the number of additional logical
partitions represented by the Partitions parameter. The LogicalVolume
parameter can be a logical volume name or a logical volume ID. To
limit the allocation to specific physical volumes, use the names of
one or more physical volumes in the PhysicalVolume parameter; otherwise,
all the physical volumes in a volume group are available for allocating
new physical partitions.

By default, the logical volume is expanded using the existing characteristics
which are displayed when you use the lslv command. To temporarily
override these existing characteristics for the new partitions only,
choose different values for these characteristics by using the flags.
The characteristics of the logical volume do not change.

The default maximum number of partitions for a logical volume is 128.
Before extending a logical volume more than 128 logical partitions,
use the chlv command to increase the default value.

The default allocation policy is to use a minimum number of physical
volumes per logical volume copy, to place the physical partitions
belonging to a copy as contiguously as possible, and then to place
the physical partitions in the desired region specified by the -a
flag. Also, by default, each copy of a logical partition is placed
on a separate physical volume.

The maximum size of a logical volume with a file system is 2GB.

Notes: 

1.	When extending a striped logical volume, the number of partitions
must be in an even multiple of the striping width.

2.	When extending a striped logical volume only the striping width
(disks striped across) is used. If there is not enough partitions
on the physical volumes, used for this striped logical volume, the
extend of the logical volume fails.

3.	It is recommended that a logical volume using a large number of
partitions (more than 800MB) be extended gradually in sections.

4.	Changes made to the logical volume are not reflected in the file
systems. To change file system characteristics use the chfs command.

5.	To use this command,  either have root user authority or
be a member of the system group.

You can use the System Management Interface Tool (SMIT) to run this
command. To use SMIT, enter:

smit extendlv

Flags

Note:	The -e, -m, -s, and -u flags are not valid with a striped logical
volume.

-a Position	Sets the intraphysical volume allocation policy (the position
of the logical partitions on the physical volume). The Position variable
can be one of the following:

m	Allocates logical partitions in the outer middle section of each
physical volume. This is the default position.

c	Allocates logical partitions in the center section of each physical
volume.

e	Allocates logical partitions in the outer edge section of each physical
volume.

ie	Allocates logical partitions in the inner edge section of each
physical volume.

im	Allocates logical partitions in the inner middle section of each
physical volume.

-e Range	Sets the interphysical volume allocation policy (the number
of physical volumes to extend across, using the volumes that provide
the best allocation). The value of the Range variable is limited by
the Upperbound variable (set with the -u flag) and can be one of the
following:

x	Allocates logical partitions across the maximum number of physical
volumes.

m	Allocates logical partitions across the minimum number of physical
volumes.

-m MapFile	Specifies the exact physical partitions to allocate. Partitions
are used in the order given in the MapFile parameter. Used partitions
in the MapFile parameter are skipped. All physical partitions belonging
to a copy are allocated before allocating for the next copy of the
logical volume. The MapFile parameter format is: PVname:PPnum1[-PPnum2
]. In this example, PVname is a physical volume name (for example,
hdisk0). It is one record per physical partition or a range of consecutive
physical partitions. PPnum is the physical partition number, which
can range from 1 to 1016.

-s Strict	Determines the strict allocation policy. Copies for a logical
partition can be allocated to share or not to share the same physical
volume. The Strict variable can be one of the following:

y	Sets a strict allocation policy, so copies for a logical partition
cannot share the same physical volume.

n	Does not set a strict allocation policy, so copies for a logical
partition can share the same physical volume.

-u Upperbound		Sets the maximum number of physical volumes for new
allocation. The value should be between one and the total number of
physical volumes in the volume group.

Examples

To increase the size of the logical volume represented by the lv05
directory by three logical partitions, enter:

extendlv lv05 3

Files

/etc	Directory where the extendlv command resides.

Related Information

The chfs command, chlv command, chpv command, lslv command, mklv command,
mklvcopy command.

The Logical Volume Storage Overview in AIX Version 4 System Management
Guide: Operating System and Devices explains the Logical Volume Manager,
physical volumes, logical volumes, volume groups, organization, ensuring
data integrity, and allocation characteristics.

The System Management Interface Tool (SMIT): Overview in AIX Version
4 System Management Guide: Operating System and Devices explains the
structure, main menus, and tasks that are done with SMIT.

AIX HACMP/6000 Concepts and Facilities.