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| JYama |
 Posted: Tue Oct 16, 2007 5:40 pm Post subject: MaxChannels |
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Master
Joined: 27 Mar 2002
Posts: 281
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Hi experts,
I have a question about MaxChennels in qm.ini.
How can I design/determine the maximum number of client connections?
Of course, I believe it depends on the requirements of applications connecting to the QMgr, but are there best practices or tips on that?
Many thanks in advance.
Last edited by JYama on Wed Oct 17, 2007 4:02 pm; edited 1 time in total |
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| fjb_saper |
| Posted: Tue Oct 16, 2007 6:34 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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Excellent red book on JMS Topologies ... Read it 
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MQ & Broker admin |
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| jefflowrey |
| Posted: Wed Oct 17, 2007 2:51 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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MaxChannels is ignored on all platforms other than zOS.
One single, poorly written, client application can consume every single channel you make available to it.
Best practices is to balance the requirements of the client interactions (request/reply, multithreaded recieving, etc.) against the capacity of the infrastructure and the funding to improve said capacity.
Intercommunications manual should have some light on resource management for channels.
In general, if you're going to run a qmgr that's hosting lots of channels - use ANYTHING OTHER THAN WINDOWS. You'll run out of network stack space long before you think you should. If you can get 3000 client connections on a similarly priced and scoped Linux box, where the windows box only gives you 1000, what value is the overhead of paying for an MS license?
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I am *not* the model of the modern major general. |
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| Gaya3 |
| Posted: Wed Oct 17, 2007 2:54 am Post subject: |
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Jedi
Joined: 12 Sep 2006
Posts: 2493
Location: Boston, US
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Hi
Just a thought....
Each MQ client channel uses between 264K - 410K bytes for processing 2K byte messages depending on traffic
rate . 100K byte messages will use up
to 700K bytes per client.
Each client channel is a process...so think of it...
Regards
Gayathri
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Gayathri
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Do Something Before you Die |
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| PeterPotkay |
| Posted: Wed Oct 17, 2007 10:02 am Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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| Gaya3 wrote: |
| Each client channel is a process...so think of it... |
...is a THREAD within its parent amqrmppa process.
Gayathri,
Do the memory stats you quote come from IBM documentation? Or from your experience (which can be quite different from another installation)
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Peter Potkay
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| tleichen |
| Posted: Wed Oct 17, 2007 11:25 am Post subject: |
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Yatiri
Joined: 11 Apr 2005
Posts: 663
Location: Center of the USA
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| jefflowrey wrote: |
| ...In general, if you're going to run a qmgr that's hosting lots of channels - use ANYTHING OTHER THAN WINDOWS. You'll run out of network stack space long before you think you should. If you can get 3000 client connections on a similarly priced and scoped Linux box, where the windows box only gives you 1000, what value is the overhead of paying for an MS license? |
Nice idea, in theory, but few of us have the luxury of rearchitecting our networks by bringing in other hardware, etc. Besides, there are IP tweaks you can do on Windows too. In the real world, you usually have to work with what you've got. 
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| jefflowrey |
| Posted: Wed Oct 17, 2007 11:38 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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| tleichen wrote: |
| Nice idea, in theory, but few of us have the luxury of rearchitecting our networks by bringing in other hardware, etc. Besides, there are IP tweaks you can do on Windows too. In the real world, you usually have to work with what you've got. |
reinstalling a different OS on the same machine is not the same as re-architecting a network... 
But yes, there are always practical considerations, and you always have to work with what you've got. But it never hurts to show mgmt how a better future for you can be less expensive for them...
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| Vitor |
| Posted: Wed Oct 17, 2007 1:23 pm Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| tleichen wrote: |
| jefflowrey wrote: |
| ...In general, if you're going to run a qmgr that's hosting lots of channels - use ANYTHING OTHER THAN WINDOWS. You'll run out of network stack space long before you think you should. If you can get 3000 client connections on a similarly priced and scoped Linux box, where the windows box only gives you 1000, what value is the overhead of paying for an MS license? |
Nice idea, in theory, but few of us have the luxury of rearchitecting our networks by bringing in other hardware, etc. Besides, there are IP tweaks you can do on Windows too. In the real world, you usually have to work with what you've got. |
If you've got large numbers of connections on a Windows machine, what you've got is suicidal management or a really dodgy job tweaking Windoze boxes. 
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| PeterPotkay |
| Posted: Wed Oct 17, 2007 3:06 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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I know its fashionable to knock Windows, but.....
I have Windows 2000 and Windows 2003 servers with 1000-1500 client connections. Been running fine for years.
I'm not saying I won't replace them with Linux when the time comes, but it won't be because they couldn't handle a lot of connections.
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Peter Potkay
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| jefflowrey |
| Posted: Wed Oct 17, 2007 3:14 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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| PeterPotkay wrote: |
| I know its fashionable to knock Windows, but..... |
There's a difference between "knocking Windows" and "being realistic about it's limitations".
Again, if you can install Linux on those exact same machines, and get 2000 - 3000 connections per box... isn't that better for everyone?
Mind you... that's not a guarantee...
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| PeterPotkay |
| Posted: Wed Oct 17, 2007 3:23 pm Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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[quote="jefflowrey"]
| PeterPotkay wrote: |
| Again, if you can install Linux on those exact same machines, and get 2000 - 3000 connections per box... isn't that better for everyone? |
Assuming I need 2-3K connections, and the Windows box proves it can't handle it, then yes.
I was responding to Vitor's comments more than anything. I've got a large # of connections to a Windows box. I suppose "large #" is relative.
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Peter Potkay
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| Gaya3 |
| Posted: Wed Oct 17, 2007 10:33 pm Post subject: |
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Jedi
Joined: 12 Sep 2006
Posts: 2493
Location: Boston, US
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| PeterPotkay wrote: |
| Gaya3 wrote: |
| Each client channel is a process...so think of it... |
...is a THREAD within its parent amqrmppa process.
Gayathri,
Do the memory stats you quote come from IBM documentation? Or from your experience (which can be quite different from another installation) |
Hi Peter,
The above one i extracted from IBM tuning and performance documentation.
Even i am simulating the same i have come across similar to that itself.
Thanks and Regards
Gayathri
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Regards
Gayathri
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| PeterPotkay |
| Posted: Thu Oct 18, 2007 4:50 am Post subject: |
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Poobah
Joined: 15 May 2001
Posts: 7722
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Can you provide the link please? Or specifically which document it lives in?
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Peter Potkay
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| Gaya3 |
| Posted: Thu Oct 18, 2007 4:57 am Post subject: |
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Jedi
Joined: 12 Sep 2006
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