Configure and tuning the operating system on AIX
When installing IBM MQ on AIX systems, there are some additional settings that must be configured.
About this task
When you install IBM MQ on AIX systems, we must configure the following operating system settings:
- File descriptors
- System resource limits
Procedure
- Increase the process limit for the number of file descriptors.
When running a multi-threaded process such as the agent process, you might reach the soft limit for file descriptors. This limit gives you the IBM MQ reason code MQRC_UNEXPECTED_ERROR (2195) and, if there are enough file descriptors, an IBM MQ FFST file.
To avoid this problem, increase the process limit for the number of file descriptors. We must alter the nofiles attribute in /etc/security/limits to 10,000 for the mqm user ID, or in the default stanza. To alter the number of file descriptors, complete the following steps:
- Check the maximum number of file descriptors available to a process running as mqm:
lsuser -a nofiles mqm- Set the value to at least 10240:
chuser nofiles=10240 mqm chuser nofiles_hard=10240 mqm
- Set the system resource limit for data segment and stack segment to unlimited using the following commands in a command prompt:
ulimit -d unlimited ulimit -s unlimitedAttention: For an mqm user ID other than root, the value unlimited might not be permitted.
What to do next
We can check the system configuration using the mqconfig command.
During high load IBM MQ can use virtual memory (swap space). If virtual memory becomes full it could cause IBM MQ processes to fail or become unstable, affecting the system.
To prevent this situation the IBM MQ administrator should ensure that the system has been allocated enough virtual memory as specified in the operating system guidelines.
For more information on configuring the system, see How to configure UNIX and Linux systems for IBM MQ.
Parent topic: Preparing the system on AIX
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