How you request BWO

You can define files as eligible for BWO in one of two ways.

Procedure

Decide which method you want to use for data sets:

vIf your data set is accessed in RLS mode, you must define the BWO option in the ICF catalog. Defining BWO in the ICF catalog requires DFSMS 1.3.

vIf your data set is accessed only in non-RLS mode, you can define the BWO option in either the ICF catalog or the CICS file definition.

Defining BWO in the ICF catalog requires DFSMS 1.3. For data sets that are accessed in RLS mode, the BWO option must be defined in the ICF catalog. Recovery attributes for data sets that are accessed only in non-RLS mode can be defined either in the ICF catalog or in the CICS FILE resource. If BWO is defined in the ICF catalog definition, by default it overrides any BWO option defined in the FILE resource. To force CICS to use the FILE resource attributes instead of the catalog recovery options, set the NONRLSRECOV system initialization parameter to

FILEDEF.

Results

Do not define BWO for the CICSPlex SM data repository using the IDCAMS DEFINE CLUSTER definition in the ICF catalog because performance is degraded. See the CICS Transaction Server for z/OS Installation Guide for information on taking backups of the CICSPlex SM data repository.

Specifying BWO using access method services

There is a BWO parameter on the access method services DEFINE CLUSTER statement.

About this task

You can specify the BWO parameter as follows:

TYPECICS

The data set is eligible for BWO in CICS.

NO The data set is not eligible for BWO.

TYPEIMS

The data set is eligible for BWO in IMS, but CICS treats this as NO.

TYPEOTHER

The data set is eligible for BWO, but CICS treats this as NO.

If you specify BWO(TYPECICS), you might need to know whether the PTF associated with APAR OA04220 has been applied to your z/OS system. That APAR extended the capabilities of VSAM so that BWO processing for RLS is no longer disabled for non-recoverable files.

vIf you specify BWO(TYPECICS), and you have also specified LOG(ALL) and a forward recovery log stream name, LOGSTREAMID(logstream_name), your file is recoverable, and the status of the PTF is not important.

vIf you specify BWO(TYPECICS), and the PTF has been applied, BWO processing is now enabled for all VSAM RLS files whether you have specified LOG(ALL), LOG(NONE) or LOG(UNDO).

206CICS TS for z/OS 4.1: Recovery and Restart Guide

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IBM SC34-7012-01 manual How you request BWO, Specifying BWO using access method services, Results