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| Goodfellas |
 Posted: Thu Jun 24, 2010 9:10 am Post subject: Non- |
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Acolyte
Joined: 26 Feb 2009
Posts: 70
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Hi,
Last edited by Goodfellas on Tue May 28, 2013 12:20 pm; edited 1 time in total |
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| Vitor |
| Posted: Thu Jun 24, 2010 9:15 am Post subject: Re: Persistent & Non-Persistent |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| Goodfellas wrote: |
| When the queue is Persistent... |
For what feels like the millionth time, queues are not persistent - messages are persistent!!!!
Persistence is an attribute set by the application when it puts the message. It may choose to use the default supplied by the queue, or may not. This has been discussed here over and over and over.
| Goodfellas wrote: |
| when the messages stay on the queue...Internally does the /var/mqm/qmgrs/<qmgr>/<queues>/q will consume the disk space or they jst write to the log...I went thru the MQ manuals but little confused. |
How can you be confused? It's fairly clear that all messages go to the queue but persistent messages are also logged.
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Honesty is the best policy.
Insanity is the best defence. |
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| bruce2359 |
| Posted: Thu Jun 24, 2010 10:16 am Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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A bit more specificity:
A queue is a virtual object (a buffer), living in virtual storage. At qmgr shutdown (and other times), messages residing in queues will be written to the /queues/queuename filesystem disk. This applies to both persistent and non-persistent messages.
A message put to a queue might never be written to the /queues disk. This occurs when the message put to the queue is immediately consumed.
As vitor said: for persistent messages, the message is also written to the /logs filesystem.
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Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| Goodfellas |
| Posted: Thu Jun 24, 2010 11:59 am Post subject: |
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Acolyte
Joined: 26 Feb 2009
Posts: 70
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Thanks
Last edited by Goodfellas on Tue May 28, 2013 12:21 pm; edited 1 time in total |
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| bruce2359 |
| Posted: Thu Jun 24, 2010 12:10 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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Not exactly. But basically, yes. The WMQ System Admin Guide gives you the calculation for sizing logs.
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I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| mqjeff |
| Posted: Thu Jun 24, 2010 12:38 pm Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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Logs only need space for active transactions.
So once the message is committed to the queue, then the 3 mb it took up in the logs can be reclaimed through various means. But this won't be immediate and it won't be something you can entirely specifically control.
But if you're using circular logs, it'll happen automatically... |
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| bruce2359 |
| Posted: Thu Jun 24, 2010 12:44 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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Read all about logging and restart in the WMQ System Admin Guide.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| fjb_saper |
| Posted: Thu Jun 24, 2010 2:39 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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And think carefully about the space requirement differences in linear and circular logs... 
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| bruce2359 |
| Posted: Thu Jun 24, 2010 2:47 pm Post subject: |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| Quote: |
| But if you're using circular logs, it'll happen automatically... |
And, with circular logs, the it mentioned might be logs full, followed by applications failing due to insufficient log space.
_________________
I like deadlines. I like to wave as they pass by.
ב''ה
Lex Orandi, Lex Credendi, Lex Vivendi. As we Worship, So we Believe, So we Live. |
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| gbaddeley |
| Posted: Thu Jun 24, 2010 3:22 pm Post subject: |
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Jedi Knight
Joined: 25 Mar 2003
Posts: 2538
Location: Melbourne, Australia
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| Goodfellas wrote: |
| So when I plan for disk space...the /var/mqm & /var/mqm/log ( seperate file systems) should have the same amount of disk space in case of persisten messages. |
Incorrect. For /var/mqm/qmgrs you mainly need to consider the total size of queued messages hardened to disk at any one time. For /var/mqm/log and using circular logging you mainly need to consider the maximum total size of perisistent messages which are uncommited at any one time. For linear logging, it depends on how often you want to release the logs that are no longer required for recovery.
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Glenn |
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