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Workload balancing in clusters

If a cluster contains more than one instance of the same queue, IBM MQ selects a queue manager to route a message to. It uses the cluster workload management algorithm, and a number of cluster workload-specific attributes, to determine the best queue manager to use.

Suitable destinations are chosen, by the cluster workload management algorithm, based on the availability of the queue manager and queue, and on a number of cluster workload-specific attributes associated with queue managers, queues, and channels. These attributes are described in the subtopics. Note: Specify the cluster workload channel attributes on the cluster-receiver channels at the target queue managers. Any balancing you specify on the matching cluster-sender channels is likely to be ignored. See Cluster channels.

After you configure the cluster workload-specific attributes, if the configuration does not behave as you expected, explore the details of how the algorithm chooses a queue manager. See The cluster workload management algorithm. If the results of this algorithm do not meet your needs, we can write a cluster workload user exit program, and use this exit to route messages to the queue of your choice in the cluster. See Writing and compiling cluster workload exits.

  • CLWLPRTY queue attribute
    The CLWLPRTY queue attribute specifies the priority of local, remote, or alias queues for cluster workload distribution. The value must be in the range 0-9, where 0 is the lowest priority and 9 is the highest.
  • CLWLRANK queue attribute
    The CLWLRANK queue attribute specifies the rank of a local, remote, or alias queue for cluster workload distribution. The value must be in the range 0-9, where 0 is the lowest rank and 9 is the highest.
  • CLWLUSEQ queue attribute
    The CLWLUSEQ queue attribute specifies whether a local instance of a queue is given preference as a destination over other instances in a cluster.
  • CLWLUSEQ queue manager attribute
    The CLWLUSEQ queue manager attribute specifies whether a local instance of a queue is given preference as a destination over other instances of the queue in a cluster. The attribute applies if the CLWLUSEQ queue attribute is set to QMGR.
  • CLWLMRUC queue manager attribute
    The CLWLMRUC queue manager attribute sets the number of most recently chosen channels. The cluster workload management algorithm uses CLWLMRUC to restrict the number of active outbound cluster channels. The value must be in the range 1 - 999 999 999.
  • CLWLPRTY channel attribute
    The CLWLPRTY channel attribute specifies the priority order for channels for cluster workload distribution. The value must be in the range 0-9, where 0 is the lowest priority and 9 is the highest.
  • CLWLRANK channel attribute
    The CLWLRANK channel attribute specifies the rank of channels for cluster workload distribution. The value must be in the range 0-9, where 0 is the lowest rank and 9 is the highest.
  • CLWLWGHT channel attribute
    The CLWLWGHT channel attribute specifies the weight applied to CLUSSDR and CLUSRCVR channels for cluster workload distribution. The value must be in the range 1-99, where 1 is the lowest weight and 99 is the highest.
  • NETPRTY channel attribute
    The NETPRTY channel attribute specifies the priority for a CLUSRCVR channel. The value must be in the range 0-9, where 0 is the lowest priority and 9 is the highest.
  • The cluster workload management algorithm
    The workload management algorithm uses workload balancing attributes and many rules to select the final destination for messages being put onto cluster queues.

Parent topic: IBM MQ cluster commands


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Last updated: 2020-10-04