Changing ACS routines

As mentioned above, ACS routines might need to be changed to implement changes in storage group, management class, storage class, or data class definitions. Defining new storage groups, storage classes, management classes, and data classes has no effect unless the ACS routines are changed to select those new constructs.

ACS routines can be changed to accomplish the following functions:

Provide initial class defaults for new collections.
Cause an object to move differently in the hierarchy by assigning a different storage class at class transition.

Tip: Defining new classes does not always mean new values for parameters; a new class can have the same parameters as an existing class. A new class might be created to make the relationship between a class and an application more understandable. This action makes it possible to modify parameters later to fit the needs of one application without affecting other applications. For example, adding a new management class that has the same backup parameter as an existing class allows you to change the backup parameter later for the new application’s objects without changing the backup requirements for other objects associated with the original class.

Attention: Changing existing constructs might not affect all objects associated with those constructs. Only those objects being stored or encountering a class transition after the construct definition is changed is affected. A change to storage class or management class takes effect at the next storage management cycle only if the object needs management (such as class transition). For example, a change in the INITIAL ACCESS RESPONSE SECONDS parameter in a storage class might not cause any or all objects with that storage class to move within the storage hierarchy.