chmdiskgrp

Use the chmdiskgrp command to modify the name that is assigned to a storage pool or to set the warning threshold for the storage pool.

Syntax

Parameters

-name new_name_arg

(Optional) Specifies the new name of the storage pool.

-warning disk_size | disk_size_percentage %

(Optional) Sets a threshold at which a warning is generated. The warning is generated the first time that the threshold is exceeded by the used-disk capacity in the storage pool. You can specify a disk_size integer, which defaults to megabytes (MB) unless the -unit parameter is specified; or you can specify a disk_size_percentage %, which is a percentage of the storage pool size. To disable warnings, specify 0 or 0%.

-size new_size

(Optional) Specifies the new size of a child pool.

Note: This parameter cannot be used with parent pools. Use addmdisk or rmmdisk to change storage pool capacity.

-unit b | kb | mb | gb | tb | pb

(Optional) Specifies the data units for the -warning parameter.

-easytier auto | on | off | measure

(Optional) Specifies whether the Easy Tier® function is on or off for this storage pool, or if it is automatically determined. -easytier is active in storage pools with multiple tiers and is balance with single tiers.

Note: -easytier must be followed by one of the following:

If -easytier is set to auto, IBM Spectrum Virtualize automatically enables Easy Tier functions when the storage pool contains MDisks from more than one tier, and enables automatic rebalancing when the storage pool contains MDisks from only one tier.
If -easytier is set to on, then Easy Tier functions are active.
If -easytier is set to off, then Easy Tier functions are inactive.
If -easytier is set to measure Easy Tier statistics are collected but Easy Tier management is disabled. (No extents are moved by Easy Tier.)

auto equates to:

on if Easy Tier is licensed or no license is required.
off if Easy Tier is not licensed and a license is required.

Specifying -easytier on enables Easy Tier:

Management of both single-tier and multi-tier pools
Auto rebalance

Extents are moved to balance the I/O load on the MDisks in the pool.

mdisk_group_id | mdisk_group_name

(Required) Specifies the ID or name of the storage pool to modify.

Description

Table 1. Parameter differences for child pools and parent pools
Parameter	Child pool usage	Storage pool usage
-name	Optional	Optional
-easytier	Cannot be used with child pools	Optional
-size	Optional	Cannot be used with parent pools
-unit	Optional	Optional
-warning	Optional	Optional

This command modifies the name, or label, assigned to a given storage pool. You can use the new name to refer to the storage pool.

The command can also be used to set the warning threshold for the storage pool. The warning threshold is the threshold which a warning is generated when it is exceeded by the used-disk capacity in the storage pool.

You can also use this command to change other settings for parent pools and child pools.

An invocation example

chmdiskgrp -name testmdiskgrp -easytier on Group0

The resulting output:

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An invocation example

chmdiskgrp -size 100 -unit tb mypool

The resulting output:

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