Determining the unit type for the control and data files

Before performing aggregate backup, you must determine the tape unit type to be allocated for the data, control, and instruction/activity log files. The unit type must be a supported tape device, as specified in the z/OS DFSMShsm Implementation and Customization Guide. It is important that the unit type is compatible with the unit type that will be used at the aggregate recovery site.

You can specify the unit type in one of two ways:

Use the SETSYS ABARSUNITNAME(unitname) command. For unitname, substitute the name of a valid unit type.
If you use this method, you can issue ABACKUP and ARECOVER commands without using their UNIT parameters. When DFSMShsm processes the ABARS control, data, and instruction/activity log files, it uses the unit type specified in the SETSYS ABARSUNITNAME command.
Specify the unit type later as part of the ABACKUP command. See ABACKUP command.

Note: If you do not specify the unit type by using the SETSYS ABARSUNITNAME parameter or if you do not use the UNIT parameter with individual ABACKUP or ARECOVER commands, DFSMShsm selects a default unit type of 3590-1.