CICS® VR
VSAM batch logging, referred to as batch logging, provides logging of updates
made to VSAM data sets by batch jobs. Two types of batch logging are available,
forward recovery logging and undo logging.
Forward recovery logging writes an after-image log record to
a forward recovery log stream for every update made to the VSAM data set by
a batch job. Therefore, if the data set becomes corrupt, CICS VR forward
recovery can be used to recreate the updates made by the batch job.
Undo logging writes a before-image log record to an undo log
stream for every update made to the VSAM data set by a batch job. Therefore,
if the batch job encounters an abend, CICS VR batch backout can be used to remove
the updates made by the failed batch job or batch job step.
Forward recovery logging, undo logging, or both can be enabled
for a VSAM data set. This section explains the tasks required to enable batch
logging for your VSAM data sets.
CICS VR
VSAM batch logging requires the following:
- Z/OS 1.6 or higher, with all necessary PTFs applied. Refer
to Operating environment for details.
- Activation of the CICS VR server address space. See Activating the CICS VR server address spacefor
details.
- All VSAM data sets that request batch logging must be SMS-managed.
- The LOGR Couple Data Set (LOGR policy) must be defined. The LOGR policy
includes the following:
- Log stream definitions
- Coupling facility list structure definitions, if applicable
- Data containing the current state of a log stream, for example; whether
a log stream is currently connected to the coupling facility structure.
For more information on the formatting a LOGR couple data set and defining
the LOGR policy, see z/OS MVS Setting Up a Sysplex, section "Preparing to
Use System Logger Applications".
CICS VR
VSAM batch logging calls the MVS™ system logger to write the log records to the MVS log
stream. The MVS system
logger is a component of z/OS®, which provides a programming interface to access
records on a log stream. For detailed information on the MVS system logger,
see the following publications:
- z/OS MVS Programming:
Assembler Services Guide
- z/OS MVS Programming:
Assembler Services Reference ABE-HSP
- z/OS MVS Setting
Up a Sysplex
The following topics are described in this section:
- Using CICS VR
VSAM batch logging
- Enabling CICS VR
VSAM batch logging
- Setting up the logging environment for CICS VR VSAM batch logging
- Detecting batch logging error conditions