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  • 1.  Queue Depth and Max Message Length of two specific queues

    Posted 04/17/26 10:59 AM

    Hello, 

    I have a situation at my work where developers are asking me to increase the max-message-length and queue depth of two dffferent queues of Producton Queuemanager running in RDQM environment.   

    I wonder if somebody can recommend a solution and also consequences (meaning how to handle the performance).  And do I need to stop/start queuemanager to increase these two parameters from default MAXMSGL.

    Thank you very much.

    Regards,
    Rajesh Verma



    ------------------------------
    RAJESH VERMA
    ------------------------------


  • 2.  RE: Queue Depth and Max Message Length of two specific queues

    Posted 04/17/26 11:36 AM

    There is no need for queue manager restart to adjust the queue property.

    You should consider the below.

    • Ask the App team what would be their possible max length. ( if they say DO NOT know, then .. ).

    As platform engineer, do the below ( https://www.ibm.com/docs/en/ibm-mq/9.4.x?topic=queue-handling-messages-greater-than-4-mb) 

    • Set the MQ Channel to 104857600 bytes  ( 100MB)
    • Set the queue manager to accept 104857600 bytes ( 100MB)
    • Set the queue to accept 104857600 bytes (100MB)

    Collect Stats for the queue, and over a period of time share the recommendation to the app team, we would reduce the size as per the stats data collected; and then reduce the Channel and queue maxMsgLen value. DO NOT change the queue manager length

    Note, doing this will also increase the total storage size of the queue manager active log and /var/mqm. So plan the sizing correctly for the queue manager.

    In RDQM, the volume group sizing is important. This will also impact DR sync if larger volume needs replication and the network is slow.



    ------------------------------
    om prakash
    Architect
    NorthwesternMutual
    Milwaukee
    ------------------------------



  • 3.  RE: Queue Depth and Max Message Length of two specific queues

    Posted 04/17/26 01:21 PM

    Thank you very much  Om Prakash!!

    Regards,

    Rajesh Verma 



    ------------------------------
    RAJESH VERMA
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    Original Message


  • 4.  RE: Queue Depth and Max Message Length of two specific queues

    Posted 04/20/26 08:14 AM
    Hello!
    Please see very important Caveats when dealing with very large message sizes!
    .
    Instructions and Warnings: How to increase the MAXMSGL for IBM MQ Queue Managers, Queues and Channels from the default 4 MB to a higher number
    .
    See Page 6 for:
     Section B: Caveats and Warnings
    .
    Thanks!
    Angel Rivera, IBM MQ Support




    Original Message


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