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  1. #1
    Join Date
    Sep 2002
    Posts
    51

    Red face Unanswered: (probably dumb) AIX / Informix question

    Please pardon my total lack of Informix expertise...but I work in a shop that let go their only informix savvy guy and now someone has asked me to figure out (1) which physical disk drives house the informix dbspaces and (2) determine if they are mirrored and then (3) come up with a plan to spread the dbspaces in a way that take advantage of multiple drives if they are clumped together.

    What I really need help with is task number 1...I dont even know where to start. Someone please help?!?! Also, anyone know of a good "Informix for Dummies" type FAQ that is AIX specific?
    -thanks
    When in doubt just ask your self,
    -WWSBD?-
    (what would Sponge Bob do?)

  2. #2
    Join Date
    May 2002
    Location
    Osnabrueck Germany
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    59
    Hi,
    try onstat -d for first informations.
    Juergen Ladwig

  3. #3
    Join Date
    Sep 2002
    Posts
    51

    Unhappy Re: (probably dumb) AIX / Informix question

    Got excited for a second, but that gives me a list of "chunks" that I am not sure how to interpret or tie back to physical disk info. The output I am getting looks like this (from onstat -d):

    700000030e657a8 40 24 32 524255 524142 PO- /dev/chunk40
    700000030e65928 41 6 32 524255 524252 PO- /dev/chunk41
    700000030e65aa8 42 26 32 524255 85873 PO- /dev/chunk42

    Is there something here that will help determine pdisks? Thanks for trying either way.
    -dnix
    When in doubt just ask your self,
    -WWSBD?-
    (what would Sponge Bob do?)

  4. #4
    Join Date
    May 2002
    Location
    Osnabrueck Germany
    Posts
    59
    Hi,
    this section with PO- must be the flags, this tell you chunk is Primary and Online, no Mirror. Pathname the name where the dbspaces/chunks are located. The 2 columns in front of PO- are the size of chunk and whats free of it in pages.
    Juergen Ladwig

  5. #5
    Join Date
    May 2002
    Location
    Osnabrueck Germany
    Posts
    59
    /dev/chunk42 is the name of a part of a disk on your system, maybe it is a symbolic link. Anyway it is not mounted.
    Juergen Ladwig

  6. #6
    Join Date
    Feb 2002
    Posts
    2,232
    The following will be very helpful:

    onstat link

    AIX Link

    The Informix Handbook - ISBN 0130122475

  7. #7
    Join Date
    Aug 2002
    Location
    Belgium
    Posts
    534
    It's always possible that these physical devices are mirrored on OS or Hardware level.
    rws

  8. #8
    Join Date
    Feb 2002
    Posts
    2,232
    Find out if this server is using raid - if it is then most of your questions will be answered (striping/mirroring ...). If you are not familiar with raid - check out the following link:

    raid

    Do you have a hardware/software specifications document for this server ? If not, this would be a good time to create/maintain one.

  9. #9
    Join Date
    Oct 2002
    Posts
    6

    question

    It sounds like what they are asking is, can you take the pdisk and determine what chunk it is linked to. Once you have that information, it is easy to determine where it lies on the database. I suggest that you get training or have your company hire a DBA to help you if you have questions.

  10. #10
    Join Date
    Aug 2002
    Location
    Belgium
    Posts
    534
    There is no way in determining what chunk is allocated to a certain physical device, starting from the device, because a chunk doesn't neccessary start at the beginning of the device. There is an offset!

    best way is to start from onstat -d and follow the symboloc links...

    With smit you can finally determine what fysical device is linked to a logical volume.
    rws

  11. #11
    Join Date
    Mar 2008
    Posts
    7
    Hello,

    I need the same information (1) as DNIX.... so i run onstat -d, and got:

    (...)
    32d8ec028 156 9 50 1000000 66647 PO- /apps/informix/databases/dbdata3_43
    (...)

    looking /apps/informix/databases/dbdata3_43

    lrwxrwxrwx 1 root other 17 Feb 15 2007 /apps/informix/databases/dbdata3_43 -> /dev/md/rdsk/d326

    and looking /dev/md/rdsk/d326

    lrwxrwxrwx 1 root root 38 Feb 23 2007 /dev/md/rdsk/d326 -> ../../../devices/pseudo/md@0:0,326,raw


    so... what "devices/pseudo/md@0:0,326,raw" means ???

    tks!

  12. #12
    Join Date
    May 2002
    Location
    Osnabrueck Germany
    Posts
    59
    Hi,
    that looks like you do have symbolic links. There must be a file: "devices/pseudo/md@0:0,326,raw" on the engine.
    Juergen Ladwig

  13. #13
    Join Date
    Mar 2008
    Posts
    7
    yes, exist:

    crw-rw-r-- 1 informix informix 85,326 Feb 23 2007 /devices/pseudo/md@0:0,326,raw

    but what it means??

    i know that crw.. means that the entry is a character special file.. but what about md@0:0,326,raw

    I need to know the physically disk, and the total/free memory n this disk..

    tks

  14. #14
    Join Date
    Dec 2003
    Location
    North America
    Posts
    146
    Perhaps this script will help, it's called "extract_onspaces.sh" and it will give you a list of the onspaces commands that were used to create the dbspaces.

    Change the .txt suffix to .sh and chmod 777 extract_onspaces.sh, and the resulting "make_chunks" file may help.
    Attached Files Attached Files

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