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| BBM |
 Posted: Sun Dec 11, 2005 2:57 am Post subject: RCDMQIMG question. |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi,
I've had a read through all the articles on RCDMQIMG on the site and read the sys. admin manual section on media images but I'm still not clear on one point.
We are taking a media image on our Win 2003 servers every evening using RCDMQIMG as we are using linear logging. However there are some scheduled jobs in place to shut down the Microsoft Biztalk MQ adapter connections into MQ before the media image is taken. This is causing Biztalk problems and I can't really see the point of doing this. By the way for those of you not familiar with Biztalk imagine it' a regular MQ application putting and getting from queues.
I was taught way back when that you can take a media image anytime regardless of MQ activity. Having read through some of the articles here, it has cast some doubt on that assumption. I can't find any IBM documentation recommending shutting down applications prior to a RCDMQIMG - but I have seen a few posts saying that this is necessary.
Does anyone have a definitive view on what is corrrect - will taking a RCDMQIMG whilst the QM is actively processing messages affect the media image adversely?
In other words does the media image record messages as well as MQ objects? I thought persistent messages were kept elsewhere in the logs so would be unaffected by whatever is in the media image..
Any replies gratefully received as I don't really want to remove these jobs only to leave us more vulnerable.
Thanks!
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| fjb_saper |
| Posted: Sun Dec 11, 2005 7:07 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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You have to distinguish between 2 uses of rcdmqimg
1) Forcing a checkpoint to be able to unload the non active logs
This can be taken any time. It should be done at least once a day.
2) In conjunction with an off line backup.
The image should be taken as the manual says after all activity on the qmgr has stopped. What does that mean? For each qmgr on the box
a) shut down all client applications that do a bindings connect
b) shut down all channels (cutting off apps in client mode)
c) take the image
d) shut down the qmgr
e) Once all qmgrs are shutdown
f) Take the offline backup (/var/mqm:/<log dirs if not under /var/mqm>
g) Restart all qmgrs
h) Restart all channels
i ) Restart all apps
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| BBM |
| Posted: Sun Dec 11, 2005 8:46 am Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Many thanks for your reply fjb_saper,
I'm pretty sure the reason we're using rcdmqimg is to checkpoint as we have the -l switch specified and we are not closing the QM at the time - in fact we never stop the QM.
This does beg the question however if one of the uses of RCDMQIMG is to merely checkpoint for housekeeping, and that's all it seems we're using it for - then there is no point in using linear logs as (due to us running our QM 24/7) we are never getting a decent media image - or are we?
Additionally, do you think I would currently realistically be able to recover objects effectively after say an accidental deletion of an MQ object file?
I apologise for my lack of knowledge on this as I have inherited the config. so have no idea why things have been set up as they are..
Thanks for your help... 
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| fjb_saper |
| Posted: Sun Dec 11, 2005 11:57 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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The checkpointing does not mean that you do not get any of the other features. It just allows you to set unused logs to inactive and archive them.
We use the java fixpack for this (MS0L ?)
Yes you are getting a decent media image and yes you can recover from your media images. On my test system I went as far as to delete the queue from the file system while the qmgr was running. On recovery from media (rcvmqobj ?) I recovered the queue and the messages.
Read the disaster recovery manual.
The reason for stopping the qmgr with the offline backup is to have a coherent image both in the logs and the rest of the file system while you do your offline backup.
Enjoy
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| BBM |
| Posted: Sun Dec 11, 2005 2:01 pm Post subject: |
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Master
Joined: 10 Nov 2005
Posts: 217
Location: London, UK
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Hi,
Thanks very much for the reply. I guess that means that what I assumed was the case is correct - you can take a media image anytime with any amount of applications connected (within reason).
And I now get the point that "to have a coherent image both in the logs and the rest of the file system while you do your offline backup."
I have definitely read the system admin manual section on disaster recovery (honest!)  - this is where my orginal query came in, there is nothing suggesting that you need to down a QM to take a media image - but I guess I must have misunderstood earlier posts on this forum on the subject.
Thanks a million - you've saved me a lot of time and trouble....I'll be arranging to schedule some downtime to properly backup the QM...
Cheers.. |
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