Recovery considerations - IBM - AS/400

There are a number of CICS/400 resources that may be defined as recoverable, namely CICS/400 files, intrapartition transient data queues, and auxiliary temporary storage queues. Protected interval control starts are always recoverable.

For a CICS/400 resource to be recoverable, it should be:

  • v Defined as recoverable in the appropriate resource definition table
  • v Registered to an OS/400 journal and journal receiver

OS/400 journals and journal receivers should not be confused with CICS/400 user journals. OS/400 journals and journal receivers are an integral part of OS/400 commitment control, which is used by CICS/400 for recovery and syncpoint management. Each recoverable resource is opened within CICS under the commitment control facilities of OS/400.

Recoverable file commitment control requirements
CICS/400 uses the commitment control facilities of the OS/400 for all recoverable files, including the TS/TD recoverable file AAEGxxxxTR. A dedicated OS/400 journal is used to coordinate resource recovery between local and remote CICS resources.

A number of command examples are provided to serve as guidelines. You need to use the command options required for your installation.

To enable a file to use OS/400 commitment control, three steps must be completed:

  1. Using the CRTJRNRCV command, create an OS/400 journal receiver.
  2. Using the CRTJRN command, create an OS/400 journal that uses this journal receiver.
  3. Using the STRJRNPF, register the physical file to the OS/400 journal.

Failure to complete these steps for the TS/TD recoverable file AAEGxxxxTR causes control region startup to fail. Figure shows an example of how to register the recoverable file to an OS/400 journal. The example program does not include any error checking or message monitoring.

Registering a recoverable file to an OS/400 journal

Registering a recoverable file to an OS/400 journal

When a control region starts, CICS/400 syncpoint control requires an OS/400 journal of its own to use for coordinating recovery between CICS systems. This journal, its receivers, and the library they reside in, are created by the control region manager, (unless they already exist). The journal is named QRCVYJ and resides in a library called QCICS.ssss, where ssss is the four-character control-region identifier. The receivers reside in the same library and are called QRCVYRnnnn, where nnnn is a four-digit decimal number. You should not associate any other resources with these journals. You should not erase the objects (library, journal, or receivers) unless you are sure that the control region has no recovery information in them, and you are recommended not to use the libraries for any other objects.

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