If the problem is cluster related, please collect below runmqras docs on problem qmgrs, changed qmgrs and all full repository qmgrs:
runmqras -qmlist QMgrName -section defs,cluster
(replace QMgrName with the actual queue manager name)
If the problem is slowness in MQ while transmitting message, usually MQ trace will be helpful.
1. Make sure that MQ trace directory (for example, /var/mqm/trace) is empty, and the file system is large enough. Please consider to mount or make a symbolic link from trace directory to a separate large file system. When the trace and queue manager are stored on same file system, if the file system is filled up, the queue manager will be stopped abnormally.
2. Start the MQ trace
strmqtrc -m QMgrName -t detail -t all
(replace QMgrName with the actual queue manager name)
3. Wait for about one minute
4. End the MQ trace
endmqtrc -a
5. Format the MQ trace files if the OS is UNIX/Linux.
cd /var/mqm/trace
dspmqtrc *.TR* (creates .FMT files)
6. Gather the data. Log in as mqm group user and use following runmqras command to gather MQ data. The command will create a zip file and display the name and location of the output file when it completes. Upload the output zip file to IBM for review.
runmqras -qmlist QMgrName -section defs,cluster,trace
(replace QMgrName with the actual queue manager name)
if you do not have enough space on the directory to collect the entire runmqras output redirect it to some of your custom temporary location where you have enough space .
https://alddit.com/generating-runmqras-output-in-custom-directory/