Storage group types

The valid values for Storage Group Type are:

VIO

Virtual I/O (VIO) storage groups are used to allocate data sets to VIO, which simulates the activity of a DASD volume. VIO storage groups do not contain any actual DASD volumes. You can put temporary data sets in VIO storage groups.

See Defining a VIO storage group for more information.

Pool

Pool storage groups contain the volume serial numbers of system-managed DASD volumes. You can use pool storage groups for both temporary and permanent data sets.

See Defining a pool storage group for more information.

Dummy

Dummy storage groups contain the volume serial numbers of DASD volumes that no longer reside on the system but that you want to treat as SMS DASD volumes. Using dummy storage groups allows existing JCL that explicitly references the DASD volumes in VOL=SER statements to work. If end users specify a VOL=SER in their JCL, and that volume serial number is in a dummy storage group list, then SMS issues a catalog request to find the desired data set rather than using the volume serial number.

Volumes in dummy storage groups cannot be used when performing volume allocations. For example, the following DD statement, where DUMMY1 is a volume in a dummy storage group, does not work:

 //DD1  DD VOL=SER=DUMMY1,UNIT=SYSDA,DISP=SHR

A dummy storage group should not contain the volume serial number of a DASD volume that exists in the system. If the DASD volume exists in the system and the data set is system-managed, no JCL errors occur but the job fails during allocation. If the DASD volume exists in the system and the data set is not system-managed, then the resulting errors depend on the type of data set. For uncataloged data sets, either the data set cannot be found or the wrong data set with the same name is found. For cataloged data sets, the job fails during allocation.

See Defining a dummy storage group for more information.

Copy Pool Backup

Copy pool backup storage groups contain the target volumes of fast replication backup requests. Ensure that the number of eligible target volumes in a copy pool backup storage group is sufficient to satisfy the needs of the number of backup versions that are specified in its associated copy pool.

To be eligible for fast replication backup, a target volume must:

Have the same track format as the source volume
Be the same size as the source volume
For FlashCopy®:
- Not be a primary or secondary volume in an XRC or PPRC volume pair
- Not be in a FlashCopy relationship at the time of the backup
For SnapShot, the volume must reside in the same RVA/SVA as the source volume.

Volumes associated with copy pool backup storage groups are for DFSMShsm use. Do not use these volumes for SMS volume allocation, or the allocation will fail.

See Defining a copy pool backup storage group for more information.

For information about using ISMF to define a copy pool, see Defining copy pools.

For more information about FlashCopy and SnapShot, see z/OS DFSMS Advanced Copy Services.

Object

Object storage groups identify an object storage hierarchy.

You can define object storage groups with no optical libraries. If you want the backup copies of objects to be written to tape, specify SETOAM statements in the CBROAMxx member of PARMLIB.

See Defining an object storage group for more information.

Object Backup

Object backup storage groups define the groups that are to be used to contain backup data and can specify one or more optical libraries that contain backup copies of objects.

The object backup storage groups can be defined with no optical libraries and have the backup copies of objects written to tape by specifying SETOAM statements in the CBROAMxx member of PARMLIB.

See Defining an object backup storage group for more information.

Tape

Tape storage groups identify storage groups to maintain system-managed tape volumes.

See Defining a tape storage group for more information.