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  • 1.  AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Mon October 02, 2006 10:01 AM

    Originally posted by: Wieckowski


    Hello,
    I have a single lpar in a p570, 32 logical cpus', 94gb memory.
    I have aioservers; configured as such;
    jaguar:/# lsattr -El aio0
    autoconfig available STATE to be configured at system restart True
    fastpath enable State of fast path True
    kprocprio 39 Server PRIORITY True
    maxreqs 32768 Maximum number of REQUESTS True
    maxservers 400 MAXIMUM number of servers per cpu True
    minservers 100 MINIMUM number of servers True
    jaguar:/#

    Number of used aioservers shows;
    jaguar:/# ps -k|grep aioserver|wc -l
    7770
    jaguar:/#

    The dba was creating a 68gb tablespace. Whenver this occurs, everything else
    "stops" on the system, until the tablespace create finishes.
    Then all the other processes will continue to run. The support center had me run perfpmr, but because these scripts will "stop" running also, they do not show anything.
    Also, currently
    ioo numfsbufs=196
    j2_nBufferPerPagerDevice=512

    Any help in resolving this would be most appreciative. This is a consistant problem and is repeatable. Thank you

    #AIX-Forum


  • 2.  Re: AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Mon October 02, 2006 10:11 AM

    Originally posted by: nh4aix


    I have seen similar occurences when creating large tablespaces. How long does it freeze for? Does the system unfreeze after the tablespace is created? I am actually not surprised it freezes, because I suspect that Oracle is initiating the SGA and you are using 68 of 96GB of memory. That is a lot of memory allocation work for AIX.
    #AIX-Forum


  • 3.  Re: AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Mon October 02, 2006 10:15 AM

    Originally posted by: Wieckowski


    Thanks for the response. The system DOES free up after the create has finished and regular system processing continues.Takes about 20-25 minutes. This needs to be fixed.
    #AIX-Forum


  • 4.  Re: AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Mon October 02, 2006 10:51 AM

    Originally posted by: Ice


    Looks like i/o pacing issue. RedBook sg246184, chapter 4.
    #AIX-Forum


  • 5.  Re: AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Mon October 02, 2006 11:05 AM

    Originally posted by: Wieckowski


    Thank you for the responce Ice. I'll research the reference you noted.
    Appreciate the time.
    #AIX-Forum


  • 6.  Re: AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Mon October 02, 2006 01:43 PM

    Originally posted by: VirtualGreg


    I've seen this before. Yes - I/O pacing could probably help during the database build. I also suggest that you set AIXTHREAD_SCOPE=S in /etc/environment just in case your bottleneck is available kernel threads. I would typically set this on every install.
    #AIX-Forum


  • 7.  Re: AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Wed November 01, 2006 06:30 PM

    Originally posted by: HajoEhlers


    Late answer but who knows
    7770 aio serves. I would check how much memory one aio servers takes. I think i have seen some thing like 4 MB/aio server and afaik the memory is pined. Maybe you just running out of memory ?

    Hajo
    #AIX-Forum


  • 8.  Re: AIX lpar "freezes" while Oracle tablespace create runs.

    Posted Thu November 02, 2006 10:41 AM

    Originally posted by: cd3lgado


    Hi

    Looks like problems with AIX VMM (Virtual Memory Manager) subsystem. If Oracle is running on JFS/JFS2 File Systems some tuning will be neccesary in order to prevent the system to make so much I/O operations cause paging activity.

    You can view your current paging top use by running:

    lsps -a

    If %used is greater than 30% then your system will be hurt by lack of RAM or bad tuning of Virtual Memory. This can lead to problems in process resources forking so your systems appears to be hanged.

    What i do is to apply some tuning hints recommended by highly used Oracle DB Servers running SAP:

    maxclient=10
    maxperm=10
    minperm=5
    you can see the current values by running:

    vmo -a | egrep "maxclient|maxperm|minperm"

    and change it by running:

    smitty chshcurvm

    Hope this helps
    #AIX-Forum


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