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| David.Partridge |
 Posted: Fri Feb 23, 2007 6:12 am Post subject: Converting from linear to circular logging |
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Master
Joined: 28 Jun 2001
Posts: 249
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One of a client's QMs regularly fills the log space as users have a habit of leaving test data on there for a long period.
We are therefore considering converting it from linear to circular logging. It is understood that the data in the queues will be lost. And I'm not convinced that linear logging buys much these days especially on a test QM (which this is).
The queue manager is a member of a number of clusters (luckily it isn't a full repository for any of these clusters).
I'd like to confirm the steps involved for the log conversion and be sure I understand the implications of doing this in the cluster environment.
I think this is what I need to do:
1) use saveqmgr to backup the definitions
2) use amqoamd to backup the permissions
3) ??? see below ???
4) delete the qmgr
5) recreate the qmgr with circular logging
6) reload the saveqmgr output
7) reload the amqoamd stuff
 Get rid of cron jobs that do rcdmqimg etc.
Do I need to do anything at step 3) above such as extract the QM from the clusters it is connected to? I think I do, but would like confirmation.
Also did I miss anything crucial (or even not so crucial).
Thanks
Dave |
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| Vitor |
| Posted: Fri Feb 23, 2007 6:22 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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You should remove the queue manager from the cluster before deleting it. This of course implies a step 9 - add new queue manager to cluster.
I agree that linear logging does not add much to a test environment.
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| bruce2359 |
| Posted: Fri Feb 23, 2007 6:40 am Post subject: |
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Read the MQ System Admin Guide, especially the sections on Recovery and Restart, and Managing Logs.
As a best practice, I make all qmgrs (test, q/a, production, identical - and all linear logs. Log usage is a function of MQPUTting and MQGETting persistent messages, changes to object definitions - that kind of thing.
Thus, test qmgrs, if used less than production qmgrs, will use less log space. For linear log qmgrs, once a log segment no longer holds active units of work, they can be archived so as to free up disk space. |
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| Vitor |
| Posted: Fri Feb 23, 2007 6:46 am Post subject: |
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Grand High Poobah
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Location: Texas, USA
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| bruce2359 wrote: |
| Thus, test qmgrs, if used less than production qmgrs, will use less log space. For linear log qmgrs, once a log segment no longer holds active units of work, they can be archived so as to free up disk space. |
Very true, but dev machines tend not to be intrinsically short of space. They fill up as rubbish accumulates, like unneeded log files, and in a dev environment it's highly unlikely you'll want to look back over old messages or recreate queue managers. Circular logs have larger initial space requirements but are self maintaining.
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| Nigelg |
| Posted: Fri Feb 23, 2007 6:50 am Post subject: |
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Joined: 02 Aug 2004
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Unless the qmgr data and log files are on different file systems there is no benefit to having a linear log system, since if they are on the same filesystem and it is lost, all the data is lost together.
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| bruce2359 |
| Posted: Fri Feb 23, 2007 7:24 am Post subject: |
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Guest
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All true.
I want test, q/a and production qmgrs to have the exact same environment, object definitions, etc.. I want programmers and admins to discover all the problems, issues and oddities, in test FIRST; so errant programs (and admin processes) don't make it into q/a or production.
An errant program sucking up lots of log space (in an MQPUT loop, for example) might not be caught in test, but would be really annoying in prod.
Disk space is cheap. Learn how to manage logs in test; then promote the process to q/a, then production. |
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| David.Partridge |
| Posted: Fri Feb 23, 2007 8:49 am Post subject: |
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Master
Joined: 28 Jun 2001
Posts: 249
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Not wishing to be akkard, but the decision to do this has been made
I don't wish to debate the merits of linear/circular logs - just want to check that my interpretation of the steps is correct, and whether I've missed anything.
Thanks
Dave |
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| kevinf2349 |
| Posted: Fri Feb 23, 2007 8:59 am Post subject: |
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Grand Master
Joined: 28 Feb 2003
Posts: 1311
Location: USA
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| David.Partridge wrote: |
Not wishing to be akkard, but the decision to do this has been made
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Then maybe this wasn't the best wording?
| David.Partridge wrote: |
| We are therefore considering converting it from linear to circular logging. |
Considering to me means...the decision has not yet been taken.
The steps look good but I would include Vitor's suggestion too.
| Quote: |
You should remove the queue manager from the cluster before deleting it. This of course implies a step 9 - add new queue manager to cluster.
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| bruce2359 |
| Posted: Fri Feb 23, 2007 9:29 am Post subject: |
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Guest
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| Read the MQ Queue Manager Clusters manual, Advanced Tasks, for step-by-step removing objects from the cluster, and removing a queue manager from a cluster. |
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| tleichen |
| Posted: Fri Feb 23, 2007 9:35 am Post subject: |
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Yatiri
Joined: 11 Apr 2005
Posts: 663
Location: Center of the USA
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Can't seem to find it on this post. What platform is this dealing with? zOS?
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| kevinf2349 |
| Posted: Fri Feb 23, 2007 11:09 am Post subject: |
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Grand Master
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| tleichen wrote: |
| Can't seem to find it on this post. What platform is this dealing with? zOS? |
Can't be z/OS...no such thing as circular logging there  |
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| tleichen |
| Posted: Fri Feb 23, 2007 11:35 am Post subject: |
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Yatiri
Joined: 11 Apr 2005
Posts: 663
Location: Center of the USA
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Yeah, that's right. I'm just not used to linear logging anywhere else... 
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