DISK I/O
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Thread: DISK I/O

  1. #1
    Join Date
    May 2001
    Location
    Delhi
    Posts
    340
    Hi,

    I am running SAP on Oracle 8i. DB Size is 203 GB.

    I ran BSTAT/ESTAT on my db. which shows maximum waits on db sequential reads.

    My current scenario is as below :

    Database is kept on Compaq MA8000 storage box. I hv 14 HDDs of 36GB cap. Under RAID 0+1 so getting space for 252 GB.

    Now I feel botleneck is there. On that Stogae Box i hv two controllers and they both work.
    Now how can i increase the I/O speed on that.

    Can anybody give me a tip on that.

    Regds
    Vijay
    --------------------------
    The Time has come ....

  2. #2
    hi,
    You storage is only 255GB and you datafiles are already 200GB, it seems you have to upgrade your disk array. Current disk system's bottleneck is not its storage capacity, but the io speed limit.
    Also consider reorganize the database , i mean reorg the table(move, or exp/imp), rebuild the index, etc.
    www.cnoug.org

  3. #3
    Join Date
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    greenwich.ct.us
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    How many filesystems? How busy is your filesystem?

    If you only have one filesystem, then yes, I/O is probably your problem. With an 8000 class box, you should have much more slots available for spindles.
    Jeff Hunter
    marist89@yahoo.com
    http://marist89.blogspot.com/
    Get Firefox!
    "I pledge to stop eating sharks fin soup and will not do so under any circumstances."

  4. #4
    Join Date
    May 2001
    Location
    Delhi
    Posts
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    Hi,

    Yes, I have only one File System. I am running all this on Win NT EE.

    So do I need to look for change of Storage Box or some other option is there.

    I am talking to my hardware guys, regarding the characterstics. of my Storage Box.

    Regards
    Vijay
    --------------------------
    The Time has come ....

  5. #5
    Join Date
    May 2001
    Location
    Delhi
    Posts
    340

    I/O on Files

    Hi,

    I hv created 6 directories on my that drive (14 drives under 0+1 raid.

    Following r the read/write statistics for that :


    Reads Writes Blk Reads Blk Writes

    m:\1 235,537,065 6,811,207 259,414,499 10,307,979
    m:\2 15,754,544 297,603 18,823,418 297,603
    m:\3 54,904,940 300,307 56,468,081 300,307
    m:\4 557,485 7,394 557,495 7,394
    m:\5 494,207 7,375 571,310 7,375
    m:\6 224,239,007 2,534,504 254,742,862 2,534,504

    Can v judge some thing from this.

    I guess I can observe the I/O for some time and then check about the I/O required and then compare it with the throughput supported by the Controllers and HDDs,.

    Am I taking the right path.

    Ideas....

    Regards
    Vijay
    --------------------------
    The Time has come ....

  6. #6
    Join Date
    Jul 2002
    Posts
    3
    hi,

    DIsk I/O or any other tuning is not one step answer
    there are many steps to consider from my point
    1. init.ora DB_FILE_MULTIBLOCK_READ_COUNT it is
    dynamic change with alter system
    2.increase db_block_buffer

  7. #7
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
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    9,092
    I wouldn't think your controllers are very busy since you only have 14 disks. Have your hardware guys look at the array statistics and find the %idle.

    You should be able to find out what %busy your filesystem is either from the OS or the Array itself. I am pretty convinced that your one filesystem is swamped.
    Jeff Hunter
    marist89@yahoo.com
    http://marist89.blogspot.com/
    Get Firefox!
    "I pledge to stop eating sharks fin soup and will not do so under any circumstances."

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