This page contains scenarios and information about the automation and recovery of Advanced Program-to-Program Communication (APPC).
Task | APPC automation and recovery scenarios |
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Startup | APPC must be started before WebSphere® Application Server for z/OS®. In theory, WebSphere Application Server for z/OS could be started before APPC, but only as long as no objects get dispatched in containers that have an IMS™ APPC LRMI associated with them. If APPC is not up before WebSphere Application Server for z/OS, and you want to use an APPC connector to talk to IMS, you must no connectivity. APPC/MVS does not have to be up for CICS®. APPC does not have to be started after VTAM®. |
Shutdown | Reverse the startup procedure. Shut down WebSphere Application Server for z/OS, APPC, then VTAM. |
Handling in-flight or indoubt transactions if there is a failure | If you are
using APPC for communications and it fails, do the following:
Note: APPC might resynchronize itself. If your transaction
is indoubt, IMS waits until you restart APPC. IMS relies
on RRS for recovery. RRS might resolve transactions that are in doubt
by handshaking with every subsystem it was communicating with before
it went down. If you are using CICS,
note that CICS has its own coordinator.
|
How to determine if APPC is running | Issue the DISPLAY APPC,LU,ALL command. If APPC is not active, it says so. In addition, the status of the logical units used by WebSphere Application Server for z/OS and/or IMS must be active or no APPC work will be successful. |
What happens to WebSphere for z/OS if APPC goes down? | Any objects attempting to use the IMS APPC PAA might not work. The server region running on behalf of the container attempting to use APPC will likely get a C9C24C05 error, indicating that an APPC ALLOCATE request was attempted and failed. Additional APPC error diagnostic information that helps to pinpoint the APPC problem is contained in the logs associated with this region. |
What happens to other subsystems if APPC goes down? | Not applicable |
Where to find more information |
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