If you have no partially filled or empty tape daily backup volumes
already assigned to the day in the backup cycle, DFSMShsm does the
following processing:
- DFSMShsm assigns another tape daily backup volume. When these
volumes are assigned, DFSMShsm tries to select volumes in the following
order:
- Unassigned tape daily backup volume. DFSMShsm then assigns it
to the current day in the backup cycle.
- Unassigned tape backup volume. DFSMShsm then assigns it as a daily
backup volume and to the current day in the backup cycle.
If no unassigned backup volumes are available, DFSMShsm requests
a scratch tape.
- DFSMShsm waits for a tape daily backup volume that is in use to
become available. If no scratch tape is available and another volume
backup task is currently using a tape daily backup volume, this volume
backup task waits for a tape daily backup volume to become available.
In a multiple DFSMShsm-host environment, before a volume backup task
enters the wait state, a five-minute timer is set. When the timer
expires, the volume backup task is dispatched, and DFSMShsm tries
to select another tape daily backup volume. If the tape daily backup
volume is still not available, the volume backup task resets the timer
and reenters a wait state. If another volume backup task dispatches
the volume backup task in the same host before the timer expires,
the timer is canceled, and DFSMShsm tries to select the tape daily
backup volume again.
- DFSMShsm stops backup processing. If DFSMShsm cannot find a tape
daily backup volume and no other volume backup task is using a tape
daily backup volume, the current volume backup task ends because no
tape daily backup volume is available.