Commands Reference, Volume 2

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 [ -mMapFile ] LogicalVolume Partitions

Description

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 that 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.

You can specify logical volumes sizes in 512 Blocks/KB/MB/GB when using the extendlv command. (See Examples.)

Notes:

When extending a striped logical volume, the number of partitions must be in an even multiple of the striping width.
When extending a striped logical volume, only the striping width (disks striped across) is used. The extend of the logical volume will fail if there are not enough partitions on the physical volumes that are used for this striped logical volume.
It is recommended that a logical volume using a large number of partitions (more than 800MB) be extended gradually in sections.
Changes made to the logical volume are not reflected in the file systems. To change file system characteristics, use the chfs command.
You must either have root user authority or be a member of the system group to use this command.
The extendlv command is not allowed on a snapshot volume group.

You can use the Volumes application in Web-based System Manager to change volume characteristics. You could also use the System Management Interface Tool (SMIT) smit extendlv fast path to run this command.

Flags

Note

The -e, -m, -s, and -u flags are invalid 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.
-s Strict	Determines the strict allocation policy. Copies of a logical partition can be allocated to share or not to share the same physical volume. The Strict variable is represented by 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. s Sets a super strict allocation policy, so that the partitions allocated for one mirror cannot share a physical volume with the paritions from another mirror. Note When changing a non superstrict logical volume to a superstrict logical volume you must specify physical volumes or use the -u flag.
-u Upperbound	Sets the maximum number of physical volumes for new allocation. The value of the Upperbound variable should be between one and the total number of physical volumes. The default is the total total number of physical volumes in the volume group. When using striped logical volumes or super strictness the upper bound indicates the maximum number of physical volumes allowed for each mirror copy.

Examples

To increase the size of the logical volume represented by the lv05 directory by three logical partitions, type:
```
extendlv lv05 3
```
To request a logical volume named lv05 with a minimum size of 10MB, type:
```
extendlv lv05 10M # 
```
The extendlv command will determine the number of partitions needed to create a logical volume of at least that size.

You can use uppercase and lowercase letters as follows:
```
    B/b       512 byte blocks
    K/k       KB
    M/m       MB
    G/g       GB
```

Files

/usr/sbin/

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 5L Version 5.2 System Management Concepts: Operating System and Devices explains the Logical Volume Manager, physical volumes, logical volumes, volume groups, organization, ensuring data integrity, and allocation characteristics.

For information on installing the Web-based System Manager, see Chapter 2: Installation and System Requirements in AIX 5L Version 5.2 Web-based System Manager Administration Guide.

The System Management Interface Tool (SMIT): Overview in AIX 5L Version 5.2 System Management Concepts: Operating System and Devices explains the structure, main menus, and tasks that are done with SMIT.