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| jeevan |
 Posted: Fri Aug 18, 2006 7:44 am Post subject: Linear log and media recovery |
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Grand Master
Joined: 12 Nov 2005
Posts: 1432
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My understanding was and still is ( I have never done it) that Linear log files are used for media recovery in addition to restarting the queue manager. But while googling ( I am preparing for test 294) I found that this is true only in Windwos and Unix platform. is that ture? I mean linear log files are used for media recovery only in these two platform ? What about other platform? Is the media recovery feature is available in all platforms? If the linear log files are not used for media recovery, what is the use of having it then ove the circular logging ?
I would appreciate any clarification /sharing your exepriences in other platforms.
thanks a lot |
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| jefflowrey |
| Posted: Fri Aug 18, 2006 7:51 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Please delete your other thread.
Other than Windows and Unix, MQ mostly runs on zSeries and iSeries.
Both of those support media recovery, although the mechanisms may be slightly different.
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I am *not* the model of the modern major general. |
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| jeevan |
| Posted: Fri Aug 18, 2006 8:06 am Post subject: |
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Grand Master
Joined: 12 Nov 2005
Posts: 1432
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My question is that is linear log requires for the media recovery in these platform or the logging systems in these platform are different?
thanks a lot |
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| jefflowrey |
| Posted: Fri Aug 18, 2006 8:25 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Logging on Z is entirely different.
iSeries is ... mostly ... a unix. So it pretty much uses the same logging principles (same source code, actually, I think).
If your MQ traffic is all non-persistent messages that never sit anywhere for very long, then you don't need media recovery.
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I am *not* the model of the modern major general. |
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| bruce2359 |
| Posted: Tue Aug 22, 2006 1:03 pm Post subject: Linear log and media recovery |
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Guest
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Circular vs. Linear Logs is an option on UNIX and Windows mid-range platforms.
Both types of logs support restart and crash recovery. Media recovery is only supported with linear logs. Control commands rcdmqimg (record media image) is used to capture ojbects to the log (for later recovery); rcrmqobj (recreate object) is used to recover (recreate) the object from image recorded in the the log with rcdmqimg.
Mainframe z/OS MQ logs are kept in VSAM Linear Data Set spaces (no relation to MQ Linear anything). iSeries logs are kept in Journals in the IFS (Integrated File System).
Refer to the System Admin Guide for description and usage of these commands, for information on logging, and for setting up logs (crtmqm). |
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| HubertKleinmanns |
| Posted: Tue Aug 22, 2006 10:50 pm Post subject: |
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Shaman
Joined: 24 Feb 2004
Posts: 732
Location: Germany
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The logging on z/OS is some sort of mixture between circular logging (active logs) and linear logging (archive logs). On iSeries MQ uses the iSeries journaling mechanism. In fact it is the same as linear logging.
I do not know, how it works on (Open)VMS, but I would guess it is similar to Unix.
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Regards
Hubert |
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