Automatic restart of primary space management or secondary space management

If you are not using secondary host promotion, and there is an interruption caused by a system outage, a cancel of DFSMShsm, or a stop of DFSMShsm, the start of DFSMShsm causes DFSMShsm to attempt to restart primary space management or secondary space management. Primary space management or secondary space management automatically restarts if all of the following conditions exist:

The time of the DFSMShsm restart is in the primary space management or secondary space management processing window and the planned start time has not been changed.
Primary space management or secondary space management is not held.
DFSMShsm is not in EMERGENCY mode.
The operator gives permission if the SETSYS REQUEST command asks permission to restart.

Otherwise, if the planned start times have not been changed, you can manually restart primary space management or secondary space management.

If you are in a multiple DFSMShsm-host environment and are using secondary host promotion, and the primary DFSMShsm host or the DFSMShsm host that runs secondary space management fails or goes into emergency mode, another DFSMShsm host is promoted to take over the unique functions of the failed DFSMShsm host. The unique functions performed by the primary DFSMShsm host include:

Space check needed for event-driven migration and recall placement of non-SMS data for interval migration.
Automatic CDS backup.
Automatic movement of backup versions from ML1 to tape.
Automatic backup of migrated data sets.
Expiration of dump copies.
Deletion of excess dump VTOC copy data sets.

When the original primary DFSMShsm host or secondary space management DFSMShsm host restarts, and is not in emergency mode, it takes over those unique functions once more. However, if the promoted host is in the process of performing some of the functions it took over for the original host, the promoted host continues with those functions to completion. The original host does not attempt to perform its unique functions until the beginning of the next window.

By default, if you manually shut down the primary DFSMShsm host or secondary space management DFSMShsm host, secondary host promotion is not invoked, with the exception of the STOP DUMP command. You can override the default and cause secondary host promotion to be invoked when you manually shut down a primary DFSMShsm host or secondary space management DFSMShsm host by using the STOP PROMOTE command.