Sysplex considerations
In a sysplex a number of z/OS operating system images collaborate in a single system image and communicate using a Coupling Facility. WebSphere MQ can use the facilities of the sysplex environment for enhanced availability.
Removing the affinities between a queue manager and a particular z/OS image allows a queue manager to be restarted on a different z/OS image in the event of an image failure. The restart mechanism can be manual, use ARM, or use system automation, if you ensure the following:
- All page sets, logs, bootstrap data sets, code libraries, and queue manager configuration data sets are defined on shared volumes.
- The subsystem definition has sysplex scope and a unique name within the sysplex.
- The level of early code installed on every z/OS image at IPL time is at the same level.
- TCP virtual IP addresses (VIPA) is available on each TCP stack in the sysplex, and you have configured WebSphere MQ TCP listeners and inbound connections to use VIPAs rather than default host names.
For more information about using TCP in a sysplex, see Redbook: TCP/IP in a sysplex, SG24-5235.
We can additionally configure multiple queue managers running on different operating system images in a sysplex to operate as a queue-sharing group, which can take advantage of shared queues and shared channels for higher availability and workload balancing.