Setting up CICS® VR change accumulation

CICS® VR CA reduces the time it takes to perform a forward recovery.

CICS® VR CA consolidates forward recovery log records into a CA data set. CICS® VR uses the CA data set in conjunction with the forward recovery log to reduce the number of log records that CICS® VR needs to apply to return the sphere to the exact state before the data was lost.

CICS® VR change accumulation consolidates all log records written for VSAM spheres since their latest backups were taken. The consolidated log records are then written to a change accumulation data set. For example, if 100 updates were made to the same record in a VSAM sphere, this would produce 100 after-image log records. CICS® VR change accumulation processing can then sort and filter these log records, copying only the most recent after-image into the CA data set. CICS® VR then can use this CA data set (instead of reading the 100 after-images) during forward recovery processing.

CICS® VR CA processing only processes log records written since the latest backups were taken for the spheres. When CICS® VR finds that new backups have been taken for VSAM spheres, the old CA data sets for the spheres are invalidated. If CICS® VR is aware of logical backups that are taken for the spheres, the process of invalidating outdated CA data sets is automated. If CICS® VR is not aware of backups created for the spheres, the latest backup dates and times must be manually entered into the CA batch jobs before execution.
Note:
CICS® VR is aware of logical backups if they have either been registered in the CICS® VR RCDS through backup notification, or if they are registered in DFSMShsm's inventory.

CA is a two step process. The next two sections cover both of these steps.