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 You are planning to install or upgrade a WebSphere MQ server on a UNIX or Linux system and need to know how to tune the operating system parameters, including kernel parameters related to inter-process communication (IPC) resources like shared memory and semaphores. Cause If you do not configure your operating system parameters properly, the WebSphere MQ server may exhaust system resources when you process your production workload. Depending on the resource which was exhausted, WebSphere MQ could return an error to the application like MQRC_RESOURCE_PROBLEM (2012), write a message to its error logs, create FDC files in the /var/mqm/errors directory, or even terminate. Resolving the problem IBM Recommendations Using the mqconfig Script Operating System Notes IPC Tuning Parameters Older Version for WebSphere MQ 6.0 and 5.3 IBM Recommendations IBM recommends default values in the WebSphere MQ documentation for several operatin...

Continuous availability to send MQ messages, with no single point of failure Linear horizontal scale of throughput, for both MQ and the attaching applications Exactly once delivery, with high availability of individual persistent messages Three messaging styles: Request/response, fire-and-forget, and publish/subscribe A hub model, with a centralized MQ infrastructure scaled independently from the application Part 1 of this article series describes the overall infrastructure topology and summarizes how it meets the above non-functional requirements for a wide range of applications. Subsequent parts show you how to configure the various components, including how to code applications that connect to the infrastructure. The topology contains four logical tiers: Figure 1. Topology overview Sender Applications sending the message. Sender gateway MQ queue managers that the sending applications connect to. Receiver gateway MQ queue managers that the receiving applicati...

[root@karthik KARTHICK]# dspmqver Name:        WebSphere MQ Version:     7.5.0.1 Level:       p750-001-130308.1 BuildType:   IKAP - (Production) Platform:    WebSphere MQ for Linux (x86-64 platform) Mode:        64-bit O/S:         Linux 2.6.32-220.el6.x86_64 InstName:    Installation1 InstDesc: InstPath:    /opt/mqm DataPath:    /var/mqm Primary:     Yes MaxCmdLevel: 750 [root@karthik KARTHICK]# [root@karthik KARTHICK]# cat mqat.ini #*******************************************************************# #* Module Name: mqat.ini                                 ...

The default for WebSphere MQ is circular logging.  If you do not specify otherwise, when you create a queue manager it will have circular logging invoked. Changing the type of logging in the qm.ini after queue manager has been created will not change the way the queue manager handles logging.  If you wish to convert from circular to linear or vice versa, you would have to recreate the queue manager specifying the new type of logging at creation time. Linear logging allows you to recreate lost or damaged data by replaying the contents of the log. This developerWorks article gives a comparison between circular and linear logs to help you evaluate which one might be best for your system: Circular logs vs. linear logs Should you choose to use linear logs, this will require that you manage the log files. Otherwise, the log files will grow infinitely and eventually fill your file system. You can archive inactive logs because they are not required for media recove...