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| MQ Message Lost |
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| silvestrelsl |
 Posted: Tue Oct 21, 2008 7:38 pm Post subject: MQ Message Lost |
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Novice
Joined: 29 Sep 2008
Posts: 10
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Architecture:
(Windows) MQ client sit in LAN A <---> router <---> ISP (dedicated link) <---> router <---> LAN B where (CICS z/OS) MQ server sit.
Scenario:
1. Put message with less than 1KB data size to a local queue.
2. Get message successfully from the same local queue.
3. Put message with more than 2KB data size to a local queue.
4. Failed to get message from the same local queue, return error 2009 (connection broken)
5. I believe that the message was lost after some time, connection session was killed automatically and I get the error code 2009.
Question:
1. Is there any firewall rules that can block a specific data packet size?
2. Is there any queue manager setting that I need to concern about?
3. I doubt the message was lost in somewhere in ISP LAN due to something related to NAT or TCP checksum.
4. Something wrong with CICS setting?
I know a solution which is buying a MQ server to be sit in LAN A, but still want to know is there any alternative without spending so much money for the license?
Thanks. |
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| fjb_saper |
| Posted: Wed Oct 22, 2008 1:01 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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If the zOS qmgr does not have the CAF (Client Attachment Facility) installed adding a distributed qmgr to your set up that connects to zOS is probably your cheapest solution. But what do I know? Confirm with your IBM rep.
If you do have the CAF it's all about firewalls, routing and MQAdmin. Standard pipe size is 4MB max chl & msg size is 100 MB. Going to 100 MB will require some admin work. The rest, make sure you are friends with the network admins
Enjoy 
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MQ & Broker admin |
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| zpat |
| Posted: Wed Oct 22, 2008 1:48 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5866
Location: UK
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Client sessions over firewalls are probably best avoided - the reason being is that firewalls tend to drop inactive sessions and the client application may be intolerant of this.
Client applications should have logic to re-connect to the queue manager after a MQRC 2009 (retry, but not in a tight loop). If it doesn't then it is not suitable and should have a local queue manager or use bindings mode.
The size of the message (at least up to a few KB) should not make any difference. Test the application with a local queue manager (you could use the free trial version) to make sure this is not simply an application bug.
MQ is not expensive compared to the business cost of losing messages. |
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| silvestrelsl |
| Posted: Wed Oct 29, 2008 5:59 pm Post subject: |
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Novice
Joined: 29 Sep 2008
Posts: 10
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I found the root cause. Just to share with everyone.
For my case, it is not firewall issue, firewall rules had been configured correctly because I managed to receive the messages which are less than 1KB size.
I tried with Windows MQ server trial version. Both sender and receiver channels are running. But, the large message would never reach my Windows MQ too.
Well, for your info, my z/OS transmit data with MTU 1400 bytes, but Windows receive data with MTU 1500 bytes. The message I sent was large and it was chopped into multi-pieces. The Windows that run with 1500 bytes MTU was not able to combine the pieces correctly.
My solution is to change the Windows registry to set my NIC instance to receive network data with 1400 bytes MTU. Now, my application (MQ client) manage to get any large message (even with 4MB size) from z/OS MQ server across multiple LAN. |
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| gbaddeley |
| Posted: Thu Oct 30, 2008 7:06 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2538
Location: Melbourne, Australia
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Maybe its just me, but I'm always amused when I read "MQ message lost". The message is not lost; it knows where it went! Its us humans who have lost track.
MQ never actually loses any messages, there is always a good reason to explain why messages apparently went astray. Its just that sometimes it is a PITA to track it down, and not everyone has deity-like knowledege of MQ.
(TGIF)
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Glenn |
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