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| csmith28 |
 Posted: Wed Oct 06, 2004 11:55 am Post subject: Wrap time for active logs Question...... |
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Grand Master
Joined: 15 Jul 2003
Posts: 1196
Location: Arizona
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AIX5.1.0.0 WMQ5.3.0.6
I have 52, 4meg circular logs on my production MQManager. During peak usages periods these logs are wrapping in about 2.5 hours. What is a comfortable log wrapp interval? I have been told that 7 days is good...
Your thoughts .....
Should I schedule a change to create more/larger logs?
I have been told that to achieve this I will have to delete the existing MQManger then recreat it. No problem, I have current saveqmgr backups to repopulate the MQManager.
I see that the maximum number of logs that can be defined is 63. So to creat enough logs to make sure I don't wrapp in one day I will have to increase the log size.
What kind of impact with this have on performance?
BTW just so you know /var/mqm/log is a separately mounted filesystem 1gig and is currently 24% used so I have space but I am not sure if I have enough space for a weeks worth of logs.
To do this without losing any data or messages in transit I am assuming that I will have to use the endmqm -w. Have all the Client Applications shutdown. Then wait for everything to stop.
This is odd. My qm.ini file shows 60 primary logs and 3 secondary yet only 52 have been created. The Administration Guide leads me to believe that the MQManager is supposed to write to the primary logs until the "LogPrimaryFile=60" threshold is met before it starts over writing old files.
Also, nothing in the Administration guide about wrap intervals recomendations.
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Yes, I am an agent of Satan but my duties are largely ceremonial. |
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| fjb_saper |
| Posted: Wed Oct 06, 2004 3:17 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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From the redbook on MQ disaster recovery:
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| A production queue manager should always run with LINEAR Logging |
Circular logging provides you only with transactional safety. There is no disaster restart recovery.
In Test/DEV Try corrupting the qmgr by deleting the physical file for the queue while the qmgr is running and then try to recover from that. Of course at time of deletion you should have some messages in the queue.
Linear logging will allow you to recover from such a scenario. Circular will not.
As well go to csd07 or csd08. CSD06 needs an additional fix for dynamic queues when writing the image (rcdmqimg)
Enjoy  |
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| csmith28 |
| Posted: Wed Oct 06, 2004 3:40 pm Post subject: |
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Grand Master
Joined: 15 Jul 2003
Posts: 1196
Location: Arizona
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| fjb_saper wrote: |
From the redbook on MQ disaster recovery:
| Quote: |
| A production queue manager should always run with LINEAR Logging |
Circular logging provides you only with transactional safety. There is no disaster restart recovery.
In Test/DEV Try corrupting the qmgr by deleting the physical file for the queue while the qmgr is running and then try to recover from that. Of course at time of deletion you should have some messages in the queue.
Linear logging will allow you to recover from such a scenario. Circular will not.
Enjoy |
But we can rebuild it. We have the technology. The saveqmgr script is a beautiful thing. If there is a "DISASTER" I can rebuild the MQManager almost as fast as Linear Logging can recover it.
I didn't create this MQManager. I inherited it. Further in the 9 years that I have been working with MQSeries I have not once seen or worked with an MQManager that uses Linear Logging.
If Linear Logging is better, then why isn't it the default?
Great advice I'll file it for later use. I would prefer to stick with Circular Logging so I don't have to worry about log maintenance.
In the mean time any suggestions on the questions I asked?
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| siliconfish |
| Posted: Thu Oct 07, 2004 6:18 am Post subject: |
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Master
Joined: 12 Aug 2002
Posts: 203
Location: USA
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| Quote: |
| But we can rebuild it. We have the technology. The saveqmgr script is a beautiful thing. If there is a "DISASTER" I can rebuild the MQManager almost as fast as Linear Logging can recover it. |
There is a difference here - we cannot compare the recreation of objects using saveqmgr with the "disaster recovery" provided by "Linear Logging".
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siliconfish |
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| csmith28 |
| Posted: Thu Oct 07, 2004 7:46 am Post subject: |
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Grand Master
Joined: 15 Jul 2003
Posts: 1196
Location: Arizona
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OK, nevermind, thanks for all the valuable suggestions.
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