RMAN question
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Thread: RMAN question

  1. #1
    Join Date
    Jun 2001
    Location
    NY
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    226
    Dear members
    I have an rman script with the following command:

    {.....
    setlimit channel chan1 kbytes 209150 readrate 28;

    }

    How do they arrive at the number 209150???

    Thanks in advance!
    roukie-dba

  2. #2
    Join Date
    Apr 2001
    Location
    London
    Posts
    725
    The readrate value is the maximum number of buffers per second. The buffer size is the result of multiplying the init.ora settings DB_FILE_DIRECT_IO_COUNT and DB_BLOCK_SIZE. Setting the readrate value inevitably involves a level of trial and error and is application- and hardware-specific
    Once you have eliminated all of the impossible,
    whatever remains however improbable,
    must be true.

  3. #3
    Join Date
    Jun 2001
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    The buffer size is the result of multiplying the init.ora settings DB_FILE_DIRECT_IO_COUNT and DB_BLOCK_SIZE.
    OS BLOCK SIZE not DB_BLOCK SIZE.
    I use the deefault DB_FILE_DIRECT_IO_COUNT of 64 having 512 OS block size.

    This is from my trace file:

    *** SESSION ID:(2.1) 2001-09-12 19:57:12.758
    kjxggin: receive buffer size = 32768
    kgxggin: SKGXN ver (2 0 dlm reference implmentation of skgxn)
    kgxggcs: Setting state to 0 0.

    Now, 32768 = 64*512.


  4. #4
    Join Date
    Apr 2001
    Location
    London
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    If you read the following article you will notice that it is DB_FILE_DIRECT_IO_COUNT and DB_BLOCK_SIZE.

    http://www.oracle.com/oramag/oracle/...ml?o20rec.html
    Once you have eliminated all of the impossible,
    whatever remains however improbable,
    must be true.

  5. #5
    Join Date
    Jun 2001
    Location
    Helsinki. Finland
    Posts
    3,938
    Good article, thanks for the link, I also knew that it is DB_BLOCK_SIZE but when I started calculating I found out that it is OS BLOCK SIZE. You know if it looks like a duck, if it quacks like a duck, then it is a duck :-)


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