For each full, DASD daily backup volume being spilled, DFSMShsm
selects a spill backup volume to contain the backup versions to be
moved. If you want DFSMShsm to use tape as spill backup volumes and
you have not specified restrictions limiting selection to tape, you
must define at least one tape as a spill volume by using the ADDVOL
command. You need not define a tape as a spill volume if you restrict
spill backup volumes to tape by specifying SPILL(TAPE) on a SETSYS
command.
DFSMShsm selects the first non-full, unallocated spill backup volume
to contain the backup versions to be moved. If a spill backup volume
is not available, DFSMShsm selects an unassigned backup volume and
assigns it as a spill backup volume.
Unassigned backup volume exists
The type of unassigned backup volume selected depends on the type
of volumes already assigned as spill backup volumes:
- If both tape and DASD spill backup volumes are defined, DFSMShsm
selects any type of unassigned backup volume
- If only DASD spill backup volumes are defined, DFSMShsm selects
only a DASD unassigned backup volume
- If only tape spill backup volumes are defined, DFSMShsm selects
only a tape unassigned backup volume
No unassigned backup volume exists
If no unassigned backup volume exists, the actions taken depend
on the type of spill backup volumes already defined:
- If both tape and DASD spill backup volumes are defined, DFSMShsm
also uses the cleanup process in an attempt to produce a usable spill
backup volume. However, if the cleanup process does not produce a
usable spill backup volume, DFSMShsm requests a scratch tape. If a
scratch tape is not available and another volume backup task is using
a tape spill backup volume, this volume backup task waits for any
spill backup volume to become available.
- If only DASD spill backup volumes are defined, DFSMShsm uses the
cleanup process in an attempt to produce a usable spill backup volume.
If the cleanup process is unsuccessful and another volume backup task
is using a DASD spill backup volume, this volume backup task waits
for a DASD spill backup volume to become available.
- If only tape spill backup volumes are defined, DFSMShsm requests
a scratch tape. If a scratch tape is not available and another volume
backup task is using a spill backup volume, this volume backup task
waits for a tape spill backup volume to become available.
Wait for a spill backup volume
In a multiple DFSMShsm-host environment, before a volume backup
task enters a wait state, a five-minute timer is set.
When the timer expires, the volume backup
task is dispatched, and DFSMShsm tries to select another spill backup
volume. If the spill 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 spill backup volume again.
No spill backup volume available
If no spill backup volume is available and another volume backup
task is not using a spill backup volume, this backup volume spill
operation ends because no spill backup volumes are available.