If no daily backup volume is available
and the number of daily backup volumes assigned to the current day
in the backup cycle is greater than or equal to the daily limit, DFSMShsm
does the following processing:
- It reuses a full DASD daily backup volume. When no unassigned
backup volumes are available, DFSMShsm either spills or cleans up
the full, unallocated, DASD daily backup volumes. If you specified
SETSYS SPILL, DFSMShsm spills the volumes. If you specified SETSYS
NOSPILL, DFSMShsm only cleans up the volumes. DFSMShsm uses the first
volume that falls below the threshold of occupancy (which you specified
with the THRESHOLD parameter of the ADDVOL command). A DASD daily
backup volume is not usable if all volumes currently assigned to this
day in the backup cycle are either being used or are full and have
been cleaned up today.
If the spill or cleanup process does not
result in a usable DASD daily backup volume, DFSMShsm requests a scratch
tape. After a scratch tape is mounted, DFSMShsm obtains the volume
serial number and internally adds the volume as a daily backup volume
assigned to the current day in the backup cycle.
- It assigns another daily backup volume. If the spill or cleanup
process does not result in a usable DASD daily backup volume, DFSMShsm
assigns another daily backup volume. When DFSMShsm assigns another
daily backup volume, it tries to select volumes in the following order:
- Unassigned daily backup volume. DFSMShsm then assigns it to the
current day in the backup cycle. This daily backup volume can be tape
or DASD.
- Unassigned backup volume. DFSMShsm then assigns it as a daily
backup volume and to the current day in the backup cycle. This backup
volume can be tape or DASD.
If no unassigned backup volume exists, DFSMShsm requests a
scratch tape. When no unassigned backup volumes are available, DFSMShsm
either spills or cleans up the full, unallocated, DASD daily backup
volumes. If you specified SETSYS SPILL, DFSMShsm spills the volumes.
If you specified SETSYS NOSPILL, DFSMShsm only cleans up the volumes.
DFSMShsm uses the first volume that falls below the threshold of occupancy
(which you specified with the THRESHOLD parameter of the ADDVOL command).
A DASD daily backup volume is not usable if all volumes currently
assigned to this day in the backup cycle are either being used or
are full and have been cleaned up today.
If the spill or cleanup
process does not result in a usable DASD daily backup volume, DFSMShsm
requests a scratch tape. After a scratch tape is mounted, DFSMShsm
obtains the volume serial number and internally adds the volume as
a daily backup volume assigned to the current day in the backup cycle.
- It waits for a daily backup volume that is in use to become available.
If DFSMShsm cannot find a daily backup volume to use and another volume
backup task is currently using an acceptable daily backup volume,
this volume backup task waits for any type of daily backup volume
to become available.
- It stops backup processing. If DFSMShsm cannot find the type of
daily backup volume it needs and no other volume backup task is using
that type of backup volume, the current volume backup task ends because
no daily backup volume is available.