Re: DBWR_IO_SLAVES and Asynchronous I/O

Dino,

Asyncrhronous I/O is set at OS level. It's not my area of expertise but that's how pre-8 always seemed to be best and 8i works fine that way too. I haven't tinkered with these settings so I don't know the rest. I'll be interested to see what others say.

Len

>Dear all,
>
>In a book, it says: (See note for source)
>"...As of 8.1, ORACLE uses the DBWR_IO_SLAVES setting to determine how
>many LGWR and ARCH I/O slaves to start; setting DBWR_IO_SLAVES to a
>value greater than 0 sets the corresponding LGWR_IO_SLAVES and
>ARCH_IO_SLAVES settings each to 4. If the option is not available on
>your system, then you may be able to use asynchronous I/O to reduce
>internal DBWR contention. With asynchronous I/O, only one DBWR process
>is started since the I/O processing is performed asynchronously."
>
>My questions:
>1.What is the definition of asynchronous I/O? Is it defined by
>DBWR_PROCESSES=1? Is it related to particular OS configurations?
>2.Why do LGWR_IO_SLAVES and ARCH_IO_SLAVES become 4 instead of 3 or 5
>when DBWR_IO_SLAVES is non-zero?
>3."If the option is not available..." What does it mean by this?
>
>Thanks in advance, Dino
>
>Note: source information:
>p.102, Kevin Leney, Oracle 8i DBA Handbook
>Ch4. Physical Database Layouts->
>Concurrent I/O Among Background Processes
>
  Received on Sat May 26 2001 - 13:47:21 CDT