IBM SC34-7012-01 manual Specifying BWO on Cics file resource definitions

vBut if you specify BWO(TYPECICS), and the PTF has not been applied, and you have not specified LOG(ALL) and a forward recovery log stream name, BWO processing for RLS remains disabled for such files. To achieve BWO for the file, you must either:

–apply the PTF,

–or specify LOG(ALL) and a forward recovery log stream name (if those actions are appropriate for the file in question).

If you omit the BWO parameter from the DEFINE statement, by default it is UNDEFINED in the ICF catalog, and the BWO attribute from the CICS file resource definition is used.

BWO(TYPECICS) is the equivalent of BACKUPTYPE(DYNAMIC) in a CICS file resource definition. All other values, including UNDEFINED, are treated by CICS as the equivalent of BACKUPTYPE(STATIC) in a CICS file resource definition. For simplicity, the CICS terms BACKUPTYPE(DYNAMIC) and BACKUPTYPE(STATIC) are used unless it is necessary to specifically mention the access method services BWO parameters.

The BWO options for the CSD are taken from the ICF catalog if they are defined there, and the system initialization parameters (CSDBKUP, CSDRECOV, and CSDFRLOG) are ignored.

Specifying BWO on CICS file resource definitions

You define a file as eligible for BWO with the BACKUPTYPE attribute on a CICS FILE resource definition in the CSD.

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If you specify BACKUPTYPE(DYNAMIC), the file is defined as eligible for BWO when the data set is opened. You must also specify RECOVERY(ALL) and FWDRECOVLOG(nn) to request forward recovery support.

BACKUPTYPE(STATIC), the default, defines a file as not eligible for BWO. In this case, if DFSMShsm is to back up a data set, all CICS files currently open for update against that data set must be closed before the backup can start.

All files opened against the same VSAM base cluster must have the same BACKUPTYPE value. That value is established by the first file opened against the cluster; it is stored in the CICS data set name block (DSNB) for the cluster. If the value for a subsequent file does not match, the file-open operation fails.

The BACKUPTYPE value in the DSNB persists across warm and emergency restarts. It is removed by a CICS cold start (unless a backout failure occurs) or by issuing EXEC CICS SET DSNAME ACTION(REMOVE) (or the CEMT equivalent) for the base cluster data set. To do this, all files that are open against the base cluster and via path definition must be closed, and the DSNB must have FILECOUNT of zero and NORMALBKOUT state.

The BACKUPTYPE attribute is ignored for user-maintained data table base clusters, because no forward recovery support is provided.

To use BWO for the CSD file, specify the CSDBKUP=DYNAMIC system initialization parameter. Also specify CSDRECOV=ALL and CSDFRLOG=nn to request forward recovery support.

Chapter 18. Backup-while-open (BWO) 207