Object and object backup storage groups

An object storage group is a storage group that defines the physical storage used for objects. For objects, the storage group allows you to define an object storage hierarchy. The object storage hierarchy can consist of:

Disk sublevel 1, which is associated with DB2 tables on a direct access storage device (DASD). The following object storage DB2 tables provide disk sublevel 1 storage for objects:
- 4 KB storage table
- 32 KB storage table
- LOB storage structure
Disk sublevel 2, which is associated with an NFS or zFS file system.
Tape sublevel 1 volumes associated with a tape library device (SMS-managed, library-resident tape volumes), and tape volumes outside of a library device (non-SMS-managed, shelf-resident tape volumes)
Tape sublevel 2 volumes associated with a tape library device (SMS-managed, library-resident tape volumes), and tape volumes outside of a library device (non-SMS-managed, shelf-resident tape volumes)
Optical volumes inside a library device (SMS-managed, library-resident optical volumes), and optical volumes outside of a library device (SMS-managed, shelf-resident optical volumes)

You can define an object storage group that does not include an optical library. If an object storage group does not include an optical library, the objects reside on DASD volumes or tape volumes and do not get moved to optical volumes.

An object can move up and down the hierarchy within a single storage group but cannot move outside of that group. Objects move within the storage hierarchy depending initially on management class and storage class criteria for the object collection, and subsequently on ACS routines.

You can define two types of storage groups for the object access method (OAM): object and object backup. An object storage group defines an object storage hierarchy. The object backup storage groups define the optical libraries or tape units that are used for backing up objects. An object or object backup storage group can be enabled by and connected to more than one system in a Parallel Sysplex®. There is no limit on the number of object or object backup storage groups defined to each system in the SMS complex. Up to two object backup storage groups can be associated with each object storage group.

You can specify two timing attributes for object and object backup storage groups: cycle start time and cycle end time. These attributes define a window of time during which the OAM Storage Management Component (OSMC) can automatically start its storage management processing for the storage group. The window occurs once each day.

You can also specify an OSMC processing system name. This attribute identifies the OAM system in the sysplex that performs OSMC processing for the object or object backup storage group. Specifying the OSMC processing system name prevents multiple systems from trying to process the same storage group at the same time. This is particularly useful when you use the cycle start time attribute to automatically start storage group processing.

To protect objects in an object storage group from deletion:

Specify deletion-protection mode. Objects cannot be deleted prior to their expiration date.
Specify retention-protection mode. Objects cannot be deleted prior to their expiration date, and the expiration date can never be changed to an earlier date.

For more information, see Defining an object storage group.

See z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Object Support for more information about managing objects.