Validation of the replication environment

InfoSphere® Classic CDC for z/OS® validates key components to ensure that your environment is ready to start replication.

Before you can start replication successfully, you must resolve any configuration problems or inconsistencies in a subscription that can prevent it from starting. The Classic Data Architect provides the Validate replication mappings function to help you troubleshoot and resolve errors when you are setting up your replication environment. You can also generate an IDCAMS LISTCAT report for the source and target VSAM spheres and compare to identify important differences that might cause validation to fail.

Validation processing enables you to fix subscription errors in the setup stage if you do not want to wait until you start replication. For example, you can try to address all the problems with a subscription that can be detected so that the subscription is more likely to start with the other subscriptions.

Subscription validation

Classic change data capture validates your subscription, replication mappings, and underlying data structures to help you to identify potential problems while you are setting up your replication environment.

The validation process compares the structure of the source and target tables in the subscription, and identifies configuration problems or inconsistencies in subscription metadata that can prevent repli:cation from starting:

  • A source database or file with incorrect augmentation
  • A VSAM subscription that references two or more VSAM data sets that use different log stream IDs for replication logging
  • A mismatch between table and column attributes at the source and target

Validation processing continues to run to completion, regardless of whether it encounters one or more of these errors.

Validation at run time

When you start replication for a subscription, Classic change data capture validates the structure of your source and target tables.

Classic change data capture validates your replication environment regardless of which of the following methods you use to start the subscription:

  • Start replication in the Management Console
  • Issue a START,REPL command to the source server
  • Mark a subscription as persistent and restart replication automatically
For VSAM data, the validation process uses the following information to validate the attributes of VSAM data sets:
  • The name of the file
  • The type of entry, such as VSAM cluster
  • The type of organization
  • The maximum record length
  • The offset of the key
  • The length of the key
  • The source and target file definitions must either be recoverable (LOG=ALL or LOG=UNDO) or non-recoverable(LOG=NONE)