Chapter 11. Advanced Copy Services 467
/SM590000Cleaning rate: No
/SM590000Primary copy source pool: Target pool
Use case
The user wants to produce a copy of a volume without affecting the availability of the volume. 
The user does not anticipate many changes to be made to the source or target volume; a 
significant proportion of the volumes remains unchanged. 
By ensuring that only changes require a copy of data to be made, the total amount of disk 
space that is required for the copy is reduced. Therefore, many Snapshot copies can be used 
in the environment. 
Snapshots are useful for providing protection against corruption or similar issues with the 
validity of the data, but they do not provide protection from physical controller failures. 
Snapshots can also provide a vehicle for performing repeatable testing (including “what-if” 
modeling that is based on production data) without requiring a full copy of the data to be 
provisioned.
For example, in Figure 11-16, the source volume user can still work on the original data 
volume (such as a production volume) and the target volumes can be accessed instantly. 
Users of target volumes can modify the content and perform “what-if” tests for example 
(versioning). Storage administrators do not need to perform full copies of a volume for 
temporary tests. However, the target volumes need to remain linked to the source. Whenever 
the link is broken (FlashCopy mapping stopped or deleted), the target volumes become 
unusable.
Figure 11-16   FlashCopy snapshot preset example
Clone
The clone preset creates a replica of the volume, which can be changed without affecting the 
original volume. After the copy completes, the mapping that was created by the preset is 
automatically deleted.
Clone uses the following preset parameters:
/SM590000Background copy rate: 50
/SM590000Incremental: No
/SM590000Delete after completion: Yes
/SM590000Cleaning rate: 50
/SM590000Primary copy source pool: Target pool