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| Could qmgr carry hidden damage after a storage failure? |
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| pcelari |
 Posted: Mon Jul 12, 2021 12:15 pm Post subject: Could qmgr carry hidden damage after a storage failure? |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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Greetings ...
during a recent storage upgrade, one of our multi-instance QM's system queues got damaged and had to be recreated. The QM seems to be running fine, but occasionally it throws segmentation faults for no clear reason.
My question is, can a QM carry hidden damage during a failure but still function normally most of the time?
If this could be the case, maybe we need to recreate the QM.
Any input would be greatly appreciated.
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pcelari
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- a master of always being a newbie |
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| bruce2359 |
| Posted: Mon Jul 12, 2021 1:25 pm Post subject: Re: Could qmgr carry hidden damage after a storage failure? |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| pcelari wrote: |
Greetings ...
during a recent storage upgrade, one of our multi-instance QM's system queues got damaged and had to be recreated. The QM seems to be running fine, but occasionally it throws segmentation faults for no clear reason. |
What is the it that throws segmentation faults? Is there an error message from MQ? An application error? Post error messages here.
How did the queues get damaged? How did you recreate them?
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| pcelari |
| Posted: Tue Jul 13, 2021 11:08 am Post subject: Re: Could qmgr carry hidden damage after a storage failure? |
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Chevalier
Joined: 31 Mar 2006
Posts: 411
Location: New York
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| bruce2359 wrote: |
How did the queues get damaged? How did you recreate them? |
MQ error logs points out to damaged queue name, so we deleted the queue and then used a backup from a day earlier to recreate the queue. I wonder if the qmgr should have been recreated.
BTW, if I shutdown a qmgr, backup all data directory, delete and recreate the qmgr, use a backup mqsc script to recreate the objects, then restore data from the backup, would that make any difference, i.e. remove any hidden damage in the qmgr?
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pcelari
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- a master of always being a newbie |
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| bruce2359 |
| Posted: Tue Jul 13, 2021 11:58 am Post subject: Re: Could qmgr carry hidden damage after a storage failure? |
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Poobah
Joined: 05 Jan 2008
Posts: 9469
Location: US: west coast, almost. Otherwise, enroute.
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| pcelari wrote: |
| bruce2359 wrote: |
How did the queues get damaged? How did you recreate them? |
MQ error logs points out to damaged queue name, so we deleted the queue and then used a backup from a day earlier to recreate the queue. I wonder if the qmgr should have been recreated.
BTW, if I shutdown a qmgr, backup all data directory, delete and recreate the qmgr, use a backup mqsc script to recreate the objects, then restore data from the backup, would that make any difference, i.e. remove any hidden damage in the qmgr? |
Nearly all of the damaged objects I've run into were caused by someone with admin authority messing with the queue-holding file system. You should never change rwx bits anywhere in the MQ file system. You should never navigate down the MQ file systems IBM installation creates.
Issuing the mqsc command to delete the damaged object, then redefine it usually works. Restoring the filesystem would re-introduce the damaged file system. No need to re-create the qmgr.
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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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| fjb_saper |
| Posted: Tue Jul 13, 2021 1:10 pm Post subject: Re: Could qmgr carry hidden damage after a storage failure? |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| bruce2359 wrote: |
| pcelari wrote: |
| bruce2359 wrote: |
How did the queues get damaged? How did you recreate them? |
MQ error logs points out to damaged queue name, so we deleted the queue and then used a backup from a day earlier to recreate the queue. I wonder if the qmgr should have been recreated.
BTW, if I shutdown a qmgr, backup all data directory, delete and recreate the qmgr, use a backup mqsc script to recreate the objects, then restore data from the backup, would that make any difference, i.e. remove any hidden damage in the qmgr? |
Nearly all of the damaged objects I've run into were caused by someone with admin authority messing with the queue-holding file system. You should never change rwx bits anywhere in the MQ file system. You should never navigate down the MQ file systems IBM installation creates.
Issuing the mqsc command to delete the damaged object, then redefine it usually works. Restoring the filesystem would re-introduce the damaged file system. No need to re-create the qmgr. |
And if you're lucky enough to use linear logging a simple recover mq object (rcrmqobj) command will do... 
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Last edited by fjb_saper on Wed Jul 14, 2021 12:49 am; edited 1 time in total |
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| bruce2359 |
| Posted: Tue Jul 13, 2021 3:01 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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| pcelari wrote: |
Greetings ...
during a recent storage upgrade, one of our multi-instance QM's system queues got damaged and had to be recreated. The QM seems to be running fine, but occasionally it throws segmentation faults for no clear reason. |
How exactly did you backup the queue? Exactly how you restore it?
Post the segmentation fault error message here.
_________________
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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