Using Management Classes

A management class is a collection of management attributes that you define. It is used to control the retention, migration, backup and release of allocated but unused space for data sets, or to control the retention, backup, and class transition of objects. Management classes let you define management requirements for individual data sets, rather than defining the requirements for entire volumes.

If you do not explicitly assign a management class to a system-managed data set, the system uses the default management class. You can define your own default management class when you define your SMS base configuration.

For objects, you can do one of the following:

Assign a management class when it is stored. Assign it explicitly, using the default specified for the collection the object belongs to, or use the management class ACS routine for a new collection.
Assign a new management class when the object is transited.
Change the management class by using the OAM Application Programming Interface (OSREQ CHANGE function).

The ACS routines can override this assignment for objects.

Figure 1 shows that you can use management class attributes to perform the following tasks:

Use early migration for old generations of a generation data group (GDG) by specifying the maximum number of generations to be kept on primary storage, and determine what to do with rolled-off generation data sets.
Delete selected old and unused data sets from DASD volumes.
Release allocated but unused space from data sets.
Migrate unused data sets to tape or DASD volumes.
Specify how often to back up data sets, and whether point-in-time copy should be used during backup.
Specify how many backup versions to keep for data sets.
Specify how long to save backup versions.
Specify the number of versions of aggregate backups to keep and how long to retain those versions.
Specify the number of backup copies of objects (1 or 2)
Establish the expiration date for objects.
Establish transition criteria for objects.
Indicate if automatic backup is needed for objects.

Figure 1. Using Management Class

By classifying your data according to management requirements, you can define unique management classes to fully automate your data set and object management. For example, you can use management classes to control the migration of CICS® user databases, DB2® user databases and archive logs, test systems and their associated data sets, and IMS™ archive logs. You can specify that DB2 image copies, and IMS image copies and change accumulation logs, be written to primary volumes and then migrated directly to migration level 2 tape volumes.

For objects, you use the class transition attributes to define when an object is eligible for a change in its performance objectives or management characteristics. For example, after a certain number of days you might want to move an object from a high-performance DASD volume to a slower optical volume. You can also use the management class to specify that the object should have a backup copy made when the OAM Storage Management Component (OSMC) is running.

If you change a management class definition, the changes affect the management requirements of existing data sets and objects that are assigned that class.

You can reassign management classes when data sets are renamed.