Availability of message processing
Messages are processed in the data center in which they are received. A message or file need not be replicated before the event is raised.
- An event is raised on the queue in the data center in which the file is received.
- WebSphere MQ accepts the event.
- Sterling B2B Integrator pulls the event from the queue and triggers business process or contract based on the event rule configuration.
- If processing is successful, status of the message is updated in Global Mailbox as success or else, it is updated as failed.
Processing of messages is performed by the Event Rule Adapter in Sterling B2B Integrator. The following sections outline the availability aspects of Event Rule Adapter in relation with the availability or non-availability of other Global Mailbox components:
How Cassandra impacts message processing
To process messages, the data center where a file is uploaded must have a majority of Cassandra nodes available. For example, if you have 3 nodes in data center 1, for messages to be processed in data center 1, you must have 2 nodes up in data center 1.
How ZooKeeper impacts message processing
During normal functioning of Global Mailbox, a minimum of 2 ZooKeeper servers must be operational across data centers for message processing to complete. The ZooKeeper watchdog process must also be running on all ZooKeeper nodes so that ZooKeeper failures can be detected, and recovery with a reduced ensemble can be initiated. While the watchdog is setting up the reduced ensemble, there is a window of time where message processing fails. The processing proceeds after the reduced ensemble is started. If the number of running ZooKeeper servers reduces to 1 or 0, all trading partner actions fail until the number of ZooKeeper servers comes back to 2 or more.
How shared disk impacts message processing
A file is processed in the data center in which it is received. The shared disk in which the file is received must be available to process the file in that data center.
How replication server and payload replication type impact message processing
Message processing is not dependent on replication server .
How WebSphere MQ impacts message processing
A multi-instance (active, passive) queue manager is required to ensure that events can be sent from Global Mailbox to Sterling B2B Integrator for processing.
WebSphere® MQ must be available in the data center where a file is uploaded for Global Mailbox to publish events (producer side) to it and for Sterling B2B Integrator to consume events from it (consumer side). For a Sterling B2B Integrator node to process a message, it must connect to the local WebSphere MQ queue to get those messages.