Informix

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  • 1.  Bringing down and up a HA cluster

    Posted 08/16/22 04:40 AM
    Hello

    Is there a preferable/right order to bring down and up a HA cluster (primary / HDR / RSS) ?

    Also is it better to pass through quiescent mode, forcing a checkpoint,...

    Thanks

    ------------------------------
    Samuel
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    #Informix


  • 2.  RE: Bringing down and up a HA cluster

    Posted 08/16/22 04:52 AM
    Hi,

    when shutting down ANY kind of Informix server, a checkpoint makes
    sense in order to minimize the startup time later on.
    The startup routine will start a recovery process which begins to recover from the latest checkpoint.
    This might take significantly longer if the checkpoint is long ago.
    That way, you can minimize the downtime by initiating a checkpoint right before the shutdown.
    My preferred way to shut down an instance is onmode -ukcy, no matter 
    what role it has.
    This does work also on a secondary instance, even though quiescent mode makes
    no real sense on this kind of server.

    Best, 

    Marcus Haarmann





  • 3.  RE: Bringing down and up a HA cluster

    Posted 08/16/22 06:30 AM
    Thanks

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    Samuel To
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  • 4.  RE: Bringing down and up a HA cluster

    Posted 08/16/22 05:07 AM
    Are you using connection manager to manage the failover in your cluster ?

    If so, then shut down servers in reverse order as specified in your FOC definition

    So if FOC ORDER=PRI,SDS,RSS then shut down RSS, then SDS, then PRI

    Regards
    Rainer

    ------------------------------
    Rainer von Bongartz
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  • 5.  RE: Bringing down and up a HA cluster

    Posted 08/16/22 06:30 AM
    I don't use a connection manager.

    So there is no preferable order to shutdown the servers PRI,HDR,RSS,
    just the down and up have to be in reverse order ?

    ------------------------------
    Samuel To
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  • 6.  RE: Bringing down and up a HA cluster

    Posted 08/16/22 08:19 AM
    Shmuel:

    No, there is not specific good or bad order to shutdown an HA cluster. Personally I would shutdown the primary first to give the secondaries a few moments to process the last couple of log buffers sent to them, but that's a minor thing. They would just process those logs on startup if they were saved or request them to be resent if they were not on disk yet at shutdown.

    There is no reason to do a separate forced checkpoint before shutting down. As long as we are talking about a proper shutdown using onmode -ky or -uky that always triggers a checkpoint as part of the shutdown.

    Art

    ------------------------------
    Art S. Kagel, President and Principal Consultant
    ASK Database Management Corp.
    www.askdbmgt.com
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  • 7.  RE: Bringing down and up a HA cluster

    Posted 08/16/22 08:28 AM
    If you use onlog you should see a checkpoint record as the last thing the engine does but I always use '- yuck' as it just easier to remember 

    Cheers
    Paul

    Paul Watson
    Oninit LLC
    +1-913-387-7529
    www.oninit.com
    Oninit®️ is a registered trademark of Oninit LLC





  • 8.  RE: Bringing down and up a HA cluster

    Posted 08/17/22 01:19 AM
    thank you all

    ------------------------------
    Samuel To
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  • 9.  RE: Bringing down and up a HA cluster

    Posted 08/20/22 05:24 AM
    Edited by System Admin 01/20/23 04:15 PM
    Rainer

    I believe the ORDER sub-parameter defined in the Connection Manager cmsm.cfg file is now deprecated, and Connection Manager adopts the Primary node's $ONCONFIG HA_FOC_ORDER parameter setting, which still has the default value...
    [ informix@informix-01 ] ~ > onstat -g cfg | grep HA_FOC_ORDER
    HA_FOC_ORDER              SDS,HDR,RSS
    ...although that doesn't make a blind bit of difference in the context of this thread.

    ------------------------------
    Kirit Rana
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