Chapter 6. Storage pools 203
Use lsmdiskgrp with storage pool name or ID as a parameter to display detailed information 
on it with CLI, as shown in Example 6-8.
Example 6-8   lsmdiskgrp output (partially shown)
IBM_Storwize:ITSOV7K:superuser>lsmdiskgrp Pool0
id 0
name Pool0
status online
mdisk_count 1
vdisk_count 5
capacity 821.00GB
extent_size 1024
free_capacity 571.00GB
<...>
6.1.4  Child storage pools
A child storage pool is a storage pool that is created within a storage pool. The storage pool 
in which the child storage pool is created is called parent storage pool.
Unlike a parent pool, a child pool does not contain MDisks. Its capacity is provided exclusively 
by the parent pool in the form of extents. The capacity of a child pool is set at creation time, 
but can be modified later nondisruptively. The capacity must be a multiple of the parent pool 
extent size and must be smaller than the free capacity of the parent pool.
A child pool cannot be created from a data reduction pool.
Child pools are useful when the capacity allocated to a specific set of volumes must be 
controlled. For example, child pools can be used with VMware vSphere Virtual Volumes 
(VVols). Storage administrators can restrict access of VMware administrators to only a part of 
the storage pool and prevent volumes creation from affecting the rest of the parent storage 
pool. 
Child pools can also be useful when strict control over thin-provisioned volumes expansion is 
needed. For example, you might create a child pool with no volumes in it to act as an 
emergency set of extents. That way, if the parent pool ever runs out of free extent, you can 
use the ones from the child pool.
Child pools can also be used when a different encryption key is needed for different sets of 
volumes.
Child pools inherit most properties from their parent pools, and these cannot be changed. The 
inherited properties include these:
/SM590000Extent size
/SM590000Easy Tier setting
/SM590000Encryption setting, but only if the parent pool is encrypted
Creating a child storage pool
To create a child pool, browse to Pools → Pools, right-click the parent pool that you want to 
create a child pool from, and select Create Child Pool, as shown in Figure 6-17 on page 204.