SAP high availability
You can configure IBM® Integration Bus to withstand software or hardware failures when working with SAP, so that IBM Integration Bus is available for as much of the time as possible.
In previous versions of IBM Integration Bus, the tRFC protocol between SAP and IBM Integration Bus (acting as the RFC server) ensures that IDocs and tRFC BAPI calls are delivered exactly once. This behavior is possible because each delivery has an associated transaction ID (TID). IBM Integration Bus monitors the progress of a delivery until SAP confirms a successful delivery. If the connection is lost or IBM Integration Bus fails before that confirmation is issued, SAP attempts to redeliver the message. By keeping a persistent record (in the TID store or transaction log), the integration node can ensure integrity and avoid a duplicate delivery.
When two .inadapter components, with the same RFC program ID, are deployed
to two integration nodes, two connections to the same RFC server are visible to SAP. If
the connection is lost to one of the integration nodes, SAP might attempt to redeliver
to the other integration node. The integration nodes have separate TID stores,
therefore, the second integration node accepts the redelivery, even though the first
integration node might have processed some (or all) of the IDocs in the packet.
In IBM Integration Bus, you can now move the TID store to a remote queue
manager that can be shared between two integration nodes. To avoid a single point of
failure, make this third queue manager a WebSphere® MQ high
availability, multi-instance queue manager. For instructions, see Setting up SAP for high availability.