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v If the file was defined with BACKUPTYPE(STATIC) and the ICF catalog
indicates that the data set is already ineligible for BWO, the ICF catalog is not
updated.
However, if the ICF catalog indicates that the data set is currently eligible for
BWO, IGWABWO makes it ineligible for BWO and sets the recovery point to the
current time. CICS issues an attention message; you should discard any BWO
backup copies already taken in a previous batch window.
File closing (non-RLS mode)
When the last file that is open for update is closed against a VSAM base cluster
data set, CICS uses the DFSMSdfp IGWABWO callable service to update the ICF
catalog to indicate that the data set is no longer eligible for BWO and to reset the
recovery point to the current time.
If a VSAM split has occurred while a file was open, CICS calls IGWABWO at
file-close time to update the ICF catalog to prevent further BWO backups. If
DFSMShsm is currently taking a BWO backup, it will discard the backup at the
end of the backup operation.
The BWO attributes indicating that a split has occurred and that the data set is
eligible for BWO are restored when the next file is opened for update against the
data set. This ensures that DFSMShsm takes the correct action if a split occurs
during backup processing, which spans CICS updating a file (causing a VSAM
split), the file being closed, and then the file being reopened.
When CICS is terminated by a normal shutdown, all CICS files are closed. The ICF
catalog is updated to suppress BWO activity during the batch window between
CICS sessions. After an uncontrolled or immediate shutdown, or if there is a
failure during file closing, the data set remains open and the BWO flags are not
reset. See “Shutdown and restart” on page 213.
Restriction for VSAM upgrade set
In some circumstances, it might not be possible to take either BWO or non-BWO
backups of a data set. The VSAM UPDATE ACB ENQs for a sphere might remain,
even though there are no files open for update against this sphere. This could
happen if a VSAM sphere contains an AIX in the upgrade set and the following
actions occur:
1. The sphere is opened for update via a VSAM path. This causes VSAM to open
for update all upgrade clusters for this sphere.
2. A file is opened for read-only against this sphere.
3. The original VSAM path is closed.
The data set is now ineligible for BWO backups because CICS file control has reset
the BWO attributes in the ICF catalog. But, until all open ACBs in the sphere are
closed, VSAM will not close the internal ACBs that are open for update, and thus
it is not possible to take non-BWO backups either.
To remedy this situation, either:
v Close all ACBs for the sphere, or
v Open for update against the base cluster data set a file that is defined with
BACKUPTYPE(DYNAMIC).
212 CICS TS for z/OS 4.1: Recovery and Restart Guide