IBM SC34-7012-01 manual Subsequent files opened when use count is not zero

vIf the file was defined with BACKUPTYPE(STATIC) and the ICF catalog indicates that the data set is already ineligible for BWO, CICS sets the BACKUPTYPE attribute in the DSNB to indicate ineligibility for BWO.

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 a message, and you can discard any BWO backups already taken in a previous batch window.

If BWO support is requested and the appropriate level of DFSMSdfp (as described in “BWO requirements” on page 204) is not correctly installed on the processor where CICS is running, the first file-open operation fails with error message DFHFC5811. Subsequent file-open operations are allowed, but CICS issues an attention message.

CICS also issues an attention message (DFHFC5813) for the first file-open operation if the appropriate levels of DFSMShsm and DFSMSdss are not installed on the processor where CICS is running. Ensure that they are installed on the processor where the BWO backup is to be made.

Subsequent files opened when use count is not zero

The following processing is done when a subsequent file is opened for update against a VSAM base cluster data set and the update use count in the DSNB for the base cluster is not zero.

The ICF catalog has already been validated and set by the first file-open operation, so CICS just checks the BACKUPTYPE attributes in the FCT and the DSNB. If they are not consistent, the file-open operation fails with error messages. You must then either correct the CEDA definition, or REMOVE the DSNB after closing all files that are open against the base cluster data set.

Subsequent files opened when use count is zero

The following processing is done when a subsequent file is opened for update against a VSAM base cluster data set and the update use count in the DSNB for the base cluster is zero.

This situation could exist in the following cases:

vAfter a warm or emergency restart of CICS, because the BACKUPTYPE attribute in the DSNB is cataloged in the global catalog and is restored at CICS restart

vWhen all files that are open against a base cluster are closed, and then one or more are reopened

CICS checks the BACKUPTYPE attributes in the FCT and the DSNB. If they are inconsistent, the file-open operation fails with error messages. Either correct the CEDA definition, or REMOVE the DSNB after closing all files that are open against the base cluster data set. If the BACKUPTYPE attributes are consistent, CICS uses the DFSMSdfp IGWABWO callable service to inquire on the BWO attributes in the ICF catalog.

vIf the file was defined with BACKUPTYPE(DYNAMIC), IGWABWO makes the data set eligible for BWO and sets the recovery point to the current time.

However, if the ICF catalog indicates that the data set is already eligible for BWO, IGWABWO resets the recovery point to the current time. CICS issues an attention message; you can discard any BWO backup copies already taken in a previous batch window.

Chapter 18. Backup-while-open (BWO) 211