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MQSeries.net Forum Index » IBM MQ Installation/Configuration Support » crtmqm hangs in linux quick beginnings

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amhest
PostPosted: Fri May 31, 2002 8:22 am    Post subject: crtmqm hangs in linux quick beginnings Reply with quote

Newbie

Joined: 31 May 2002
Posts: 2

I am facing a wierd behavior on RedHat 7.2 with MQ Series 5.2.0-4. When I run "crtmqm -q venus.queue.manager" as mqm the command creates a directory /var/mqm/qmgrs/venus!queue!manager and creates appropriate log files and mqs.ini entries. However, the command hangs (for hours) failing to produce an error or any output.

The system is not under disk, memory, or CPU load. I have verified all of the group and ownership settings and am running the command as mqm, though the same behavior happens as root.

I turned on tracing. The only interesting entry I found was:

Code:

09:59:58.924850    24346.1          AMQ_USE_THREADED_SEMREQ is set
09:59:58.924913    24346.1          Indefinite wait required


Does the AMQ_USE_THREADED_SEMREQ setting mean anything? Google can't find a single reference to it.

Another oddity is that if I type "ps -aux" the crtmqm process shows up as user 'mqm' but if I run "top" it shows up as running as 'root'.

Any help would be greatly appreciated.
Evan.
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mrlinux
PostPosted: Fri May 31, 2002 9:20 am    Post subject: Reply with quote

Grand Master

Joined: 14 Feb 2002
Posts: 1261
Location: Detroit,MI USA

Well did you tune the kernel parms, it looks like a semaphore issue, do you have the quick beginnings book for linux ????
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amhest
PostPosted: Fri May 31, 2002 9:39 am    Post subject: Linux kernel changes Reply with quote

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Joined: 31 May 2002
Posts: 2

I made the shmmax change. I did not mess with the max process count because I am way under the limits. Without MQ there are only ~65 processes running:

Code:

bash-2.05$ ps -aux | wc -l
     68


The system is not under heavy load with a crtmqm command in its:

Code:

bash-2.05$ top
 12:59pm  up 52 days, 7 min,  1 user,  load average: 0.14, 0.15, 0.16
66 processes: 65 sleeping, 1 running, 0 zombie, 0 stopped
CPU states:  0.1% user,  0.5% system,  0.0% nice, 99.2% idle
Mem:   126212K av,  120464K used,    5748K free,    8628K shrd,    3620K buff
Swap:  347720K av,   27136K used,  320584K free                   42228K cached


I can go after the kernel changes but it seems odd that the max process count is causing what I agree is acting like a semaphore problem.

Evan.
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mrlinux
PostPosted: Fri May 31, 2002 6:58 pm    Post subject: Reply with quote

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Joined: 14 Feb 2002
Posts: 1261
Location: Detroit,MI USA

I believe you will find the max process to be around 4090 I think which I dont see as an issue it looks more like the system is trying to acquire a semaphore and cant (remember this is MY OPINION and is subject to be wrong)
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bduncan
PostPosted: Sun Jun 02, 2002 9:33 pm    Post subject: Reply with quote

Padawan

Joined: 11 Apr 2001
Posts: 1554
Location: Silicon Valley

Hmm... I've had no problem running MQ5.2 on a vanilla Redhat 7.2 installation. I didn't need to tweak the kernel like I've done on other platforms. I have experienced the crtmqm command hanging forever though. It's just been so long I can't quite remember what caused it in my particular case.
But in lieu of any specific advice, I'd recommend cranking up the kernel parameters. Also, are you running any other semaphore/file-handle/shared-memory hungry applications on that same machine like Oracle, Websphere, etc..? If so, sometimes increasing the kernel parameters to those recommended in the Quick Beginnings Guide isn't enough. You'll have to take the values recommended for MQ, the values recommended for the other app, and sum them together (which usually means you're setting everything to the hard limit anyway...)
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