Architecture of the administrative task scheduler in a data sharing environment

In a data sharing environment, each member of a data sharing group is associated with its own administrative task scheduler. Each member is associated with its own administrative task scheduler, even when those members run in the same z/OS system. The administrative task schedulers share their resources and interface.

The task list is shared by all administrative task schedulers in a data sharing group, accessing a shared task file on shared storage (VSAM data set defaulting to prefix.TASKLIST, where prefix is the Db2 catalog prefix) and a redundant task list in the Db2 system table SYSIBM.ADMIN_TASKS.

The following figure shows a data sharing group with two Db2 members and their associated administrative task schedulers.

Begin figure description. This figure shows a data sharing group with two members and the corresponding administrative task scheduler configuration. End figure description. — Figure 1. Administrative task schedulers in a data sharing group

Tasks are not localized to a administrative task scheduler. They can be added, removed, or executed in any of the administrative task schedulers in the data sharing group with the same result. However, you can force the task to execute on a given administrative task scheduler by specifying the associated Db2 subsystem ID in the DB2SSID parameter when you schedule the task. The tasks that have no affinity to a given Db2 subsystem are executed among all administrative task schedulers. Their distribution cannot be predicted.