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| pcelari |
 Posted: Fri Apr 24, 2015 11:50 am Post subject: Multi-instance QM fail-over - Loss of non-persistent msg |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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Hello,
it seems non-persistent messages on a queue will be lost after a fail-over of multi-instance qmgr. Is this the designed behavior?
Given all messages are stored in the shared FS, I wonder why non-persistent messages can be lost without a qmgr restart.
any insight would be appreciated.
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pcelari
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- a master of always being a newbie |
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| mqjeff |
| Posted: Fri Apr 24, 2015 12:04 pm Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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Non persistent messages can be lost simply by restarting a queue manager.
Non persistent messages can be lost under a large set of different scenarios.
You can read about NPMCLASS. |
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| markt |
| Posted: Sat Apr 25, 2015 6:05 am Post subject: |
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Knight
Joined: 14 May 2002
Posts: 504
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what on earth makes you think that
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| all messages are stored in the shared FS, |
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| fjb_saper |
| Posted: Sat Apr 25, 2015 8:24 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20696
Location: LI,NY
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If you cannot afford to loose a message, it (the message) should be persistent. It is the responsibility of the sender to set the persistence of the message... 
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MQ & Broker admin |
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| pcelari |
| Posted: Mon Apr 27, 2015 6:32 am Post subject: |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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| markt wrote: |
what on earth makes you think that
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| all messages are stored in the shared FS, |
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Granted, I made a thinking error.
The messages could well be in memory at the time of the fail-over. Wonder if there is way to force the messages be written to the FS. Generally, I prefer to avoid using persistent messages.
thanks a lot,
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pcelari
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- a master of always being a newbie |
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| mqjeff |
| Posted: Mon Apr 27, 2015 6:32 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| This thread contains all the answers you need. |
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| zpat |
| Posted: Mon Apr 27, 2015 6:43 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5849
Location: UK
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Yes there is a way to force the message to the FS - make the message persistent.
Incidentally if you are using modern SAN storage - then you can change the TripleWrite to SingleWrite, which makes it faster.
There are other ways to improve persistent message throughput - such as increasing the number of log buffer pages.
Either you want to protect against system failure or you don't. If you do and you are concerned about performance - there are various ways to tune it.
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Well, I don't think there is any question about it. It can only be attributable to human error. This sort of thing has cropped up before, and it has always been due to human error.
Last edited by zpat on Mon Apr 27, 2015 11:57 pm; edited 1 time in total |
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| RogerLacroix |
| Posted: Mon Apr 27, 2015 1:34 pm Post subject: |
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Jedi Knight
Joined: 15 May 2001
Posts: 3253
Location: London, ON Canada
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| pcelari wrote: |
| I made a thinking error. |
Well, there you have it (the root of your problem).
Non-persistent should ONLY EVER be used for messages that CAN be lost. The answer is really that simple. 
Regards,
Roger Lacroix
Capitalware Inc.
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