DBIO_EXPECTED

Hi experts,
Oracle says that the i/o performance analysis is affected by the dbio_expected parameter which should be set to the average time(in microseconds) it takes to read a single database block from the disk with typical values range from 5000 to 20000 microseconds.
For example :-
exec dbms_advisor.set_default_task_parameter ('ADDM','dbio_expected',8000);
My question is how can we say that 8000 microseconds is good. How we can identify this average time

Another way would be to benchmark your storage using some tools like ORION and see what's the latency that's available for it. As per Oracle, 8000 is a timing that's supported and provided by most if not all, storage vendors.
HTH
Aman....

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    Hi ,
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  • How to estimate DBIO_EXPECTED

    Hi all. I would like to estimate dbio_expected. I know the guide definition, Measure the average read time of a single database block for your hardware. This measurement needs to be taken for random I/O, which includes seek time if you use standard hard drives. But I don't know how to do it in my system. Does anyone have ever estimated it?
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    Jordi X. Martin wrote:
    Hi all.
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    JordiHi Jordi,
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