Defining a Log Stream for APPC/MVS

To provide resource recovery for protected conversations, APPC/MVS requires the names of local and partner LU logs, and the negotiated syncpoint capabilities for each local/partner LU pair. This information needs to be available and accurate for successful resynchronization after a failure. To store this information, APPC/MVS uses a system logger log stream that your installation must set up.

To set up an APPC/MVS log stream, your installation follows the same procedure that is required for other system logger applications:

1. Plan for and set up the APPC/MVS log stream.
2. Plan and set up DASD space needed for APPC/MVS log data sets and staging data sets.
3. Define the APPC/MVS log and staging data sets to global resource serialization in the GRSRNLxx parmlib member.
4. Define authorization to system logger resources for APPC/MVS.
5. Format the LOGR couple data set, identify it to the sysplex, and make it available.
6. Add, update, or delete APPC/MVS policy data (the APPC/MVS log stream and its associated coupling facility structure) in the LOGR policy using the IXCMIAPU utility. APPC/MVS supports DASD ONLY configuration for its log stream in a single system environment.
7. Update the CFRM sysplex couple data set with information on the coupling facility structure associated with the APPC/MVS log stream.
8. Activate the LOGR subsystem.

While doing the setup for an APPC/MVS log stream in a parallel sysplex environment, keep in mind that if an APPC/MVS log stream is defined with DASD ONLY configuration, APPC/MVS from only one system can connect to the log stream. Only APPC/MVS from this one system processes protected conversations. Other systems in a parallel sysplex fail to process protected conversations and issue message ATB203I to document the return and reason codes received from the system logger IXGCONN service.