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| SilentWind |
 Posted: Thu Dec 07, 2006 7:06 pm Post subject: The connections numbers |
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Acolyte
Joined: 11 Jan 2006
Posts: 58
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Hi,
I would like to ask some questions:
1) How many connections per client can Websphere MQ 6.0 support up to?
2) How many connections in total can it support?
Thanks. |
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| vennela |
| Posted: Thu Dec 07, 2006 7:52 pm Post subject: |
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Jedi Knight
Joined: 11 Aug 2002
Posts: 4055
Location: Hyderabad, India
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1. As many as you want
2. As many as you want
But your QMGR should be configured to accept that many number |
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| wschutz |
| Posted: Fri Dec 08, 2006 5:29 am Post subject: |
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Jedi Knight
Joined: 02 Jun 2005
Posts: 3316
Location: IBM (retired)
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| SilentWind |
| Posted: Fri Dec 15, 2006 12:16 am Post subject: |
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Acolyte
Joined: 11 Jan 2006
Posts: 58
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| Quote: |
1. As many as you want
2. As many as you want
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Correct me if I am wrong, but I believe setting the queue manager properties of 'Max channels' and 'Max active channels' should set the max client connections. The max number seems to be 9999.
Ok, I have just finished reading the documentation and there is much statistics on message sizes, throughput, roundtime, CPU usage, memory, persistency, etc. The only section I could find on client connections were in
Websphere MQ for Windows V6.0 - Performance Evaluations V1.1 in Chapter 2: Performance Headlines
2.2 Client Channels Test Scenario
2.2.3 Client Channels
where they tested 5250 MQI clients.
So my question is:
For Java clients and a pub-sub environment, how do I configure for the maximum number of clients? |
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| Vitor |
| Posted: Fri Dec 15, 2006 2:19 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| SilentWind wrote: |
| Quote: |
1. As many as you want
2. As many as you want
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Correct me if I am wrong, but I believe setting the queue manager properties of 'Max channels' and 'Max active channels' should set the max client connections. The max number seems to be 9999.
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Well yes, but I think the point is you don't "want" 10,000 channels on a single queue mamanger. You just don't... 
| SilentWind wrote: |
So my question is:
For Java clients and a pub-sub environment, how do I configure for the maximum number of clients? |
The exact answer to your question is "by setting max channels on the queue manager". If your question is actually "how do I determine the maximum number of clients for MY pub-sub environment", this is a question like "how long is a piece of string". Take reference of the performance reports, the capacity of the machine running the queue manager, your design & expected message volumes and from this determine how many simultanious clients you expect.
Then do a performance test to see how close you got! 
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| SilentWind |
| Posted: Tue Dec 19, 2006 6:10 pm Post subject: |
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Acolyte
Joined: 11 Jan 2006
Posts: 58
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Hi Vitor,
Thanks for the reply!
Am I right in saying that in MY pub-sub environment, I may not reach the maximum number of channels set in the qm? i.e. my client count cannot reach 9999?
If I need to connect 10,000 clients, what could be a possible solution? |
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| jefflowrey |
| Posted: Tue Dec 19, 2006 7:05 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Let's say you *do* get 10,000 clients connected to your one queue manager.
Then your queue manager goes down.
There are now 10,000 people sitting around getting paid to not do work.
Maybe you should have more than one queue manager in there.
_________________
I am *not* the model of the modern major general. |
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| SilentWind |
| Posted: Tue Dec 19, 2006 9:54 pm Post subject: |
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Acolyte
Joined: 11 Jan 2006
Posts: 58
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| Quote: |
Let's say you *do* get 10,000 clients connected to your one queue manager.
Then your queue manager goes down.
There are now 10,000 people sitting around getting paid to not do work.
Maybe you should have more than one queue manager in there. |
Ok I understand your point. But I just would like to focus on the number of connections part for now. Hence I would like to ask besides the max channels in qm, what are the other possible factors that limit the client connections? e.g. OS of the MQ server, number of available ports etc etc. |
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| Vitor |
| Posted: Wed Dec 20, 2006 12:09 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| SilentWind wrote: |
Am I right in saying that in MY pub-sub environment, I may not reach the maximum number of channels set in the qm? i.e. my client count cannot reach 9999?
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No, my point was in a similar vein to jefflowrey. That number of connections to a queue manager builds a massive single point of failure. IMHO you want to spread them around rather more than that.
As to the physical limits, you should look through the support packs. I know the connections take up memory and other resources, but it varies from platform to platform. I would not be surprised to discover there's no a definative answer.
I am interested to know why you're pursuing the route of maxing out the connections on a single queue manager. What are the drivers for this decision?
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| SilentWind |
| Posted: Wed Dec 20, 2006 1:20 am Post subject: |
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Acolyte
Joined: 11 Jan 2006
Posts: 58
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| Quote: |
| I am interested to know why you're pursuing the route of maxing out the connections on a single queue manager. What are the drivers for this decision? |
Thats a good question to ask. Well, it all boils down to my pub-sub environment.
I have approximately 500 clients deployed using MQ JMS client programs which I built. Each client is listening to different number of JMS topics, ranging from 5-20. Also, I have learnt that in MQ implementation, 1 JMS topic is equivalent to 1 connection to the MQ server (I have confirmed this using netstat). Therefore in the worst case, I would have 500x20 = 10,000 connections to the MQ server. With my max channels at 9999, I can only connect 4500 clients. I am still trying to figure out this number out.
And why don't I have more than 1 queue manager? This is because with more than 1 queue manager, my 4500 is reduced. I have a load-balancing plan at the back of my head with more qm, but until I resolve this connection problem, the "1 qm" problem has a lower priority.
Hope that clarifies things. |
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| Vitor |
| Posted: Wed Dec 20, 2006 1:31 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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Thank you for a very well presented scenario.
| SilentWind wrote: |
| Also, I have learnt that in MQ implementation, 1 JMS topic is equivalent to 1 connection to the MQ server |
Important Point / Disclaimer - My knowledge of Java is at much the same level as my knowledge of the dark side of the Moon. Beware of rubbish strewn over the rest of this post.
I'm surprised to discover there's a 1-1 correlation between topic & connection. It's a restriction I was previously unaware of and wonder why this is so. It was my (possibly flawed) understanding that each subscriber connected to the queue manager, submitted a subscription request and a queue on which to receive the matching publications & could perform this 1-n times on a single session. Is this not the case? What is the case? Links answering these questions, and recommended additional reading on the subject, welcomed.
I seek to broaden my mind. Especially when it comes to Java.
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| SilentWind |
| Posted: Wed Dec 20, 2006 5:50 pm Post subject: Help |
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Acolyte
Joined: 11 Jan 2006
Posts: 58
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| Quote: |
| I'm surprised to discover there's a 1-1 correlation between topic & connection. |
Well, this relevation not only stunned me, but caused me some very worrying sleepless nights!
I believe the problem (feature? ) is related to MQ history. As Websphere MQ is actually meant for P2P communication, pub-sub functionality is significantly weaker, hence we have other extensible products of MQ Event Broker/Message broker. It seem to me that the behaviour of pub-sub seems to mimick p2p by creating a unique tcp connection for a topic.
Actually, I have been in touch with some IBM staff, and they have kindly explained to me that such is the behaviour. However they are unable to explain the following:
(a) How exactly do I arrive at 4500 connections?
(b) How to get more connections?
Any form of explanation or help would be very greatly appreciated. I would be glad to explain any doubts on my client environment, or JMS program or MQ settings as I am familiar with all the above factors. |
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| Vitor |
| Posted: Wed Dec 20, 2006 11:52 pm Post subject: Re: Help |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| SilentWind wrote: |
Actually, I have been in touch with some IBM staff, and they have kindly explained to me that such is the behaviour. However they are unable to explain the following:
(a) How exactly do I arrive at 4500 connections?
(b) How to get more connections?
Any form of explanation or help would be very greatly appreciated. |
If IBM can't explain it, that's me reaching for my hat & heading for the door. Especially with Java. 
Thinking back, if I ever did pub/sub with the base product it was back in the day (5.2?) and never with Java. Commercially I've always used WMB or one of it's ancestors.
Perhaps a better Java person or an IBMer in here will be able to assist you.
_________________
Honesty is the best policy.
Insanity is the best defence. |
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| Nigelg |
| Posted: Thu Dec 21, 2006 1:15 am Post subject: |
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Grand Master
Joined: 02 Aug 2004
Posts: 1046
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With the 4500 you are probably hitting some constraint other than MaxChannels. This can easily be tested; if the problem is MaxChannels the qmgr error logs will contain an error msg - I forget the AMQ number - saying so. If it is not, then there may be another error msg saying what the actual problem is, i.e. what resource is running short.
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MQSeries.net helps those who help themselves.. |
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| SilentWind |
| Posted: Thu Dec 28, 2006 1:05 am Post subject: |
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Acolyte
Joined: 11 Jan 2006
Posts: 58
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| Quote: |
| With the 4500 you are probably hitting some constraint other than MaxChannels. This can easily be tested; if the problem is MaxChannels the qmgr error logs will contain an error msg - I forget the AMQ number - saying so. If it is not, then there may be another error msg saying what the actual problem is, i.e. what resource is running short. |
Ok, I forgot to check the logs.
I got this error
| Code: |
DD/MM/YYYY HH:MM:SS Process(2948.1) User(XXXX) Program(amqzxma0.exe)
AMQ5009: WebSphere MQ agent process XXXXX has terminated unexpectedly.
EXPLANATION:
Websphere MQ has detected that an agent process has terminated unexpectedly. The queue manager connection(s) that this process is responsible for will be broken.
ACTION:
Use any previous FFSTs to determine the reason for the failure. Try to eliminate the following reasons before contacting your IBM support center.
1) A user has inadvertently terminated the process.
2) The system is low on resources. Some operating systems terminate processes to free resources. If your system is low on resources, it is possible that the operating system has terminated the process so that an new process can be created.
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A previous FFST reads like this:
| Code: |
DD/MM/YYYY HH:MM:SS Process(2948.1) User(XXXX) Program(amqzxma0.exe)
AMQ6184: An internal WebSphere MQ error has occurred on queue manager XXXXXXX
EXPLANATION:
An error has been detected, and the WebSphere MQ error recording routine has been called. The failing process is process 2948.
ACTION:
Use the standard facilities supplied with your system to record the problem identifier, and to save the generated output files. Contact your IBM support center. Do not discard these files until the problem has been resolved. |
My question is: What resource is my server lacking? RAM? CPU? Harddisk? |
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