Group attachments and subgroup attachments

Utilities and applications that use TSO, batch, DL/I batch, the RRSAF, the CAF, or DB2I (Db2 Interactive) to connect to Db2 have two methods for specifying the member to which they want to connect.

The first method is to specify the name of the subsystem. The second method is to use the group attachment name, which acts as a generic name for all the members of a data sharing group. The group attachment name can be used in place of the name of the Db2 subsystem that runs on the z/OS® system from which the job was submitted. If you use a group attachment name, you can also use a subgroup attachment name to provide more organization and control over connection requests.

If you specify a group attachment name, the utility or application does not need to be sensitive to a particular member, which makes it easier to move jobs around the Parallel Sysplex® as needed. The utility or application connects to the first active group member that it finds. However, when the name of a subsystem is the same as the group attachment name, the utility or application attempts to connect to the member first. If that member is not started and group attachment name processing is not disabled, the utility or application attempts to connect to the next group member that is active. (NOGROUP is the group override and is available for CAF and RRSAF.)

If you do not explicitly specify a subsystem name or group attachment name, Db2 uses DSN as the name of the intended subsystem. As with any application program, make sure you are accessing the set of Db2 libraries with the correct DSNHDECP programming defaults.