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.

If you specify the BACKUPTYPE(DYNAMIC) option, the file is defined as eligible for BWO when the data set is opened. This definition applies only to the base cluster in a VSAM sphere. If a VSAM data set is accessed through one or more alternate indexes, the path definitions for the alternate index must also be defined as eligible for BWO processing. You must also specify the RECOVERY(ALL) and the FWDRECOVLOG(nn) options 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 that are 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.

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.