Re: Max IO size

"Kevin Brand" <kevin.brandx_at_tel.gte.com> wrote in message news:<9n63cl$926$1_at_news.gte.com>...
> Check that your multiblock_read_count setting didn't get truncated to an OS
> limit. If you set it to 64, which would mean "64 8k blocks to be read in a
> multiblock read", you'd look for a 512k read. However, if the OS limit is
> 256k reads, then Oracle would truncate multiblock_read_count to 32 ( based
> on your 8k block size ).
>
> Take a look at the setting in the SGA to make sure it matches your init.ora
> setting, as Oracle will quietly set it to the platform specific max value.
>
> -Kevin
> "Connor McDonald" <connor_mcdonald_at_yahoo.com> wrote in message
> news:3B966E0C.3BA_at_yahoo.com...
> > I've got a sun (solaris 2.8) box with with datafiles under vxfs. After
> > setting
> >
> > - maxphys to 512k
> > - vxiomax to 512k
> > - db block size to 8k
> > - multiblock read count to 64
> >
> > I had presumed that I could get a ceiling of half a meg per read on
> > (say) a full table scan, but a level 8 10046 trace yields a ceiling of
> > 256k (ie p3 in the waits is 32 not 64)
> >
> > I'll be repeating the test under a raw partition tomorrow but comments
> > anyone ? As a related question, anyone know what Oracle's SSTIOMAX is
> > under the various versions (say from 7.3)
> >
> > Cheers
> >
> > --
> > ==============================
> > Connor McDonald
> >
> > http://www.oracledba.co.uk
> >
> > "Some days you're the pigeon, some days you're the statue..."

Hi,
I'm running on Solaris 2.6 and Oracle 817 and I have a lot of "direct path read/write" waits.
I think that it can be concerned with the db_file_multiblock_read_count and OS Max I/O.

Where can I detect the current Value of Max I/O on the OS and how can I set it.

thanks a lot
Chris Received on Thu Sep 06 2001 - 07:39:50 CDT