Re: db_writer_processes, dbwr_io_slaves, db_block_lru_latches and

Ethan,

AIX definietly does async io. Talk to your sysadmin about configuring it.

Do you see a lot of 'kproc' processes with ps?

( I think it's kproc, don't have an S80 handy :)

Those are for async io.

And since you're on EMC, it may not make any difference anyway, depending on your EMC configuration and transaction rate.

They typically have very large caches and delayed physical writes.

Jared

On Tuesday 05 June 2001 13:50, Post, Ethan wrote:
> I have read about 20 different articles dealing with the setting of these
> parameters and I'm still tremendously confused. The first problem is
> determining if your OS supports async_io. Most of the info I find says
> "most" operating systems do but then I find that this is perhaps only true
> on raw volumes. I'm creating the INIT file for a large DB and the docs
> recommend setting up multiple db_writer_processes and setting disk_async_io
> to false in all cases. However, I have already found some recommends that
> are definitely wrong. We are installing on an RS6000 4*500 Mhz box with
> 2GB RAM. Should I configure 4 db_writer_processes right off the bat or
> should I go with one and wait to see if there is actually some DBWR
> contention? I have set up one db_block_lru_latch for each
> db_writer_process since I have no additional pools configured at this time.
> Then the next question is whether I go with dbwr_io_slaves instead? It
> seems the recommends have change since Oracle 8 and then changed back with
> 8i. By the way the disk is going to be EMC.
>
> If someone can put together a nice little decision tree for this that would
> be cool.
>
> Regrettably thick headed,
> Ethan Post
>
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