Re: Cannot start multiple dbwrs when using I/O slaves

Hi,
Database version and OS information would be helpful. But in sort: DB_WRITER_IO_SLAVES simulates asynch IO. They do not perform asynch IO. They are helpful only when the operating system donot support asynch IO. If your OS supports Asynch IO, then you should use multiple DBWR, and set disk_asynch_io=TRUE

One problem of this is, if the I/O volume is very high, so that the OS could not handle it, In that case there is a chance that asynch I/O
will time out. This will lead to crash of the database.

Only in that case you should use slaves with setting disk_asynch_io=FALSE

You can not use DBWR_IO_SLAVES and multiple DBWR process at the same time.

Hope this helps,
Thanks,
Saikat Chakraborty

"yls177" <yls177_at_hotmail.com> wrote in message news:c06e4d68.0311242117.6491e1f1_at_posting.google.com

> i have multiple "Cannot start multiple dbwrs when using I/O slaves"
> entries in my alert file. upon checking the parameters, i have this
> database writer and database I/O slaves set at the same time.
>
> upon doing some reading, realise that i cant have these two at the
> same time unless i have DB_BLOCK_LRU_LATCHES too, am i right?
>
>
> however, what my colleague managed to start oracle, is not to
> configure any of these parameters but instead 2 other which are the
> number of processes and lock_sga. afterwhich, the multiple dbwrs
> messages are gone.
>
> comments?

-- 
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG