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| Client Connections |
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| wmqiguy |
 Posted: Wed Apr 30, 2003 12:18 pm Post subject: Client Connections |
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Centurion
Joined: 09 Oct 2002
Posts: 145
Location: Florida
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Created a dll that goes throught the whole routine.
Connect open close, etc. Puts a request message in one queue and gets the reply from another.
Everything is hunky.
Waiting for the twist weren't ya?
Stress is killing it...and not much at that.
If we create a test harness that calls this dll individually (25 calls = 25 separate threads) we eventually start to bounce into some TCPIP errors. Specifically, 10061, connection refused. Roughly, the first 20 are successful, then bam...no dice.
The dll is using the client channel table and is using the same svrconn channel.
Thanks for all your help in advance. |
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| JohnMN |
| Posted: Wed Apr 30, 2003 1:59 pm Post subject: |
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Novice
Joined: 26 Feb 2003
Posts: 19
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I don't know the answer, but if I "think out loud" maybe I can give you a couple of questions that might help. They're not in any particular order -- just a bunch of questions to ask.
We run a z/OS (MVS) system that handles well over 100 clients at a time to the same server-conn channel, so there's no "magical number" of incoming clients.
First thing I would do is find out which side the error is really occurring on.
My first reaction when reading this is that it's the server side that's giving the 10061 error. What kind of system is the server? Is it up to the task of handling 25 incoming client channels?
You can probably test whether the error is on the client or server side by loading your dll onto 2 or 3 separate machines and trying to connect 10 or 15 times from each system.
If you get the 10061 when there are a total of 20 channels, then you probably need to look at the server side. Actually, the error would start showing up at the same time on each of the client systems.
If it's a client side issue, then you'll most likely get the 10061 after different numbers of channels have been started, depending on the individual machine and the load on each machine.
Is it consistent? Do you always get the error after 20 channels? Does it seem to depend on the load, either on the server side or the client side?
How are you seeing the 10061 error? Is there also an MQSeries error message along with it?
Hope that helps some.
John |
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| zpat |
| Posted: Wed Apr 30, 2003 11:33 pm Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5866
Location: UK
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We have 2500 MQ clients connected to a single OS/390 queue manager.
There is an upper limit for client connections defined somewhere as a default for all queue managers, but it's easy to increase it. |
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| wmqiguy |
| Posted: Thu May 01, 2003 5:05 am Post subject: |
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Centurion
Joined: 09 Oct 2002
Posts: 145
Location: Florida
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UPDATE:
We have suspected and have confirmed that this was not an MQSeries issue, but a TCPIP/OS issue. Essentially, we had reached the limit of how many "hits" could come through a single socket.
Essentially, can I send 20 people through a door...yes.
Can I send 20 people through the door at once....no.
Here's more for those that are curious. As we stepped up the robustness of the platform, the more we could handle simultaneously. We started on a WIN2000 Workstation, went to a Server, then Solaris, and finally OS390. Each one was able to handle increasing amounts.
Reason for the test is that we are getting ready to deploy a client dll on about 10,000 workstations. We projected that at max (conservative estimate) we would have 20-30 simultaneous hits. We are using WIN2000 Server and Solaris machines. When we modeled it on a workstation we were at the lower limits of an acceptable level. On our server class machines we have LOTS of leeway.
Thanks for the responses! 
Todd |
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| bower5932 |
| Posted: Thu May 01, 2003 8:23 am Post subject: |
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Jedi Knight
Joined: 27 Aug 2001
Posts: 3023
Location: Dallas, TX, USA
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| Check out the ListenerBacklog parameter of the TCP section of the qm.ini file. It is documented in the Intercommunication manuals, and it sounds like it is what you are looking for. |
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| EddieA |
| Posted: Mon May 05, 2003 10:05 am Post subject: |
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Jedi
Joined: 28 Jun 2001
Posts: 2453
Location: Los Angeles
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Ron,
Yes, that was the problem. But no matter how high you make that parameter, you can't make the Backlog any bigger that the underlying TCP/IP implementation allows. That is 5 for Workstation, 200 for Server.
Cheers,
_________________
Eddie Atherton
IBM Certified Solution Developer - WebSphere Message Broker V6.1
IBM Certified Solution Developer - WebSphere Message Broker V7.0 |
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