Also, are your sql statements performing unnecessary physical I/O? Can those be tuned to
reduce it?
But, implement one solution at a time, though, to see what impact it has.
Regards,
- Kirti
- Tanel_Põder <tanel.poder.003_at_mail.ee> wrote:
> > How are "free buffer waits" (below) to be addressed?
>
> Your DBWR probably isn't able to write dirty buffers to disk fast enough.
>
> See if you have disk_asynch_io = true set.
> If you're running on regular cooked filesystem (not QuickIO) then you should
> probably increase the number of db writer processes or dbwr slaves (instead
> of using OS simulated asynch IO).
>
> Btw, if you are on raw devices or QuickIO and using kernelized asynch IO, I
> would still keep the number of dbwr's greater than 1 in heavily IO intensive
> environment.
>
> Also, number of buffer cache LRU latches (controlled by
> _db_block_lru_latches) might become a bottleneck in your env (lots of CPUs +
> heavy IO).
>
> Also, you might want to increase your buffer cache (tm ;) to give dbwr a
> little more breathing room.
>
> Btw, why do you want to have separate 4 controllers for log files? I get the
> need for 2 ones (the IO generated by archiver won't disturb lgwr's IO), but
> why the additional 2? Just for having more time for archiver before lgwr
> hits the same controller again or are you using software striping over
> different controllers (or multiplexing) for redologs?
>
> Tanel.
>
>
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Received on Mon Jul 26 2004 - 13:14:33 CDT
