Removing a messaging engine from a cluster
We can reduce the number of messaging engines configured for a cluster bus member by removing a messaging engine.
Before you remove a messaging engine from a cluster, drain it of messages and prevent further messages being sent to it. Otherwise, when a messaging engine is removed, all messages currently stored on that messaging engine are deleted. Any messages in transit to the removed messaging engine might remain on the sending messaging engine on a remote queue point and require manual cleanup.
When we remove messaging engines from a cluster, remove them in numerical order from highest to lowest so as to avoid a situation where, for example, there are messaging engines numbered 001 and 002 and not 000. This is to avoid problems if we use WS-Notification, which attaches special significance to the first-created messaging engine in a cluster. See WS-Notification troubleshooting tip Problems can occur when deleting administered subscribers and messaging engines.
When we remove a messaging engine from a cluster, all message points and their messages are deleted, so if the cluster has a queue destination configured, some of the messages stored for that queue might be lost.
To remove a messaging engine from a cluster:
Tasks
- In the navigation pane, click Service integration -> Buses -> bus_name -> [Topology] Bus members.
- In the content pane, click the cluster from which we want to remove a messaging engine. The Bus member detail panel is displayed.
- In the content pane, under Additional properties, click Messaging engines. A list of messaging engines for the cluster is displayed.
- In the content pane, select the messaging engine to remove.
- Click Remove messaging engine.
- Save changes to the master configuration.
The messaging engine is removed from the cluster.
We can also use the deleteSIBEngine command to remove a messaging engine from a cluster.
What to do next
Remember: When we remove a messaging engine, WebSphere Application Server (base) does not delete the data store tables or the file store files automatically.
- For a data store, to recreate the same messaging engine, we must first delete the previous set of tables. If we create a messaging engine and use existing tables, the tables must be empty so that the messaging engine can function correctly. Refer to the documentation for our chosen relational database management system (RDBMS) for information about how to delete tables. However, if we created a data store with default settings, we do not need to delete previous tables.
- For a file store, we might want to delete the file store files to reclaim disk space.
Related:
Messaging engines Message production and consumption using remote message points Bus members List the messaging engines for a cluster bus member Manage messaging engines with administrative commands Correcting the messaging engine policy Deleting a redundant core group policy Emptying the data store for a messaging engine Deleting files following removal of a messaging engine Modify the messaging engine policy for a cluster bus member deleteSIBEngine command Messaging engine troubleshooting tips