Re: filesystemio_options option on solaris 9 sparc 64-bit (Oracle 10g)
- From: "LS Cheng" <exriscer@xxxxxxxxx>
- To: "DBA Deepak" <oracle.tutorials@xxxxxxxxx>
- Date: Wed, 21 Nov 2007 12:15:39 +0100
Hi
I shall point you to a ML note *462072.1* which talks about Linux but the
theory applies for other UNIX flavours as well.
I had recent experience with DIO in AIX, the database actually went worse
when DIO was enabled it was because the application did many full table
scans even though I doubled buffer cache.
Thanks
--
LSC
On Nov 21, 2007 12:01 PM, DBA Deepak <oracle.tutorials@xxxxxxxxx> wrote:
> Hi LS,
>
> Can you please help me in understanding how direct i/o will make the
> FTS of a big table slower?
>
> If FTS becomes slow then is it not recommended to use directio where
> FTS of large tables are done?
>
> As per many experts we should always use directio+ufs combination for
> oracle files related disks.
>
> Deepak
>
> On Nov 21, 2007 4:08 PM, LS Cheng <exriscer@xxxxxxxxx> wrote:
> > one option is brute force :-P
> >
> > create a very big table and full scan it, direct i/o will be slower
> because
> > filesystem buffer would help in this case!
> >
> > --
> > LSC
> >
> >
> >
> >
> > On Nov 21, 2007 10:11 AM, DBA Deepak < oracle.tutorials@xxxxxxxxx>
> wrote:
> > >
> > >
> > >
> > > Hi John,
> > >
> > > Sorry for the late response. Even after mounting the filesystem with
> > > "forcedirectio" option am unable to see a non-zero value as the third
> > > parameter value to the ioctl() calls. I did the same experiment as
> > > mentioned in your previous mail.
> > >
> > > Would you please tell is there any alternative to verify whether the
> > > system is using directio or not?
> > >
> > > Regards,
> > >
> > > Deepak
> > >
> > >
> > >
> > >
> > > On Oct 18, 2007 12:45 PM, John Hallas <john.hallas@xxxxxxxxxx> wrote:
> > > >
> > > >
> > > >
> > > > Have the filesystems been mounted with direct_io option?
> > > >
> > > >
> > > > ________________________________
> > > >
> > > >
> > > > From: oracle-l-bounce@xxxxxxxxxxxxx
> > [mailto:oracle-l-bounce@xxxxxxxxxxxxx ]
> > > > On Behalf Of DBA Deepak
> > > > Sent: 17 October 2007 19:39
> > > > To: John Hallas
> > > > Cc: oracle-l
> > > > Subject: Re: filesystemio_options option on solaris 9 sparc 64-bit
> > (Oracle
> > > > 10g)
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Hi John,
> > > >
> > > >
> > > >
> > > > Thanks for your help. In my environment filesystemio_options is set
> to
> > > > SETALL
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Still it is not using directIO as per your test. My server is sparc
> > Solaris
> > > > 9, 64 bit with Oracle 10.2.0.3.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Can you please help me in troubleshooting the same. Am I missing
> > anything?
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ________________________________
> > > >
> > > > BJSS Limited, 1st Floor Coronet House, Queen Street, Leeds LS1 2TW.
> > > > Registered in England with company number 2777575.
> > > > http://www.bjss.co.uk
> > > >
> > > >
> > > >
> > >
> > >
> > >
> > > --
> > > Regards,
> > >
> > > Deepak
> > > Oracle DBA
> > > --
> > > //www.freelists.org/webpage/oracle-l
> > >
> > >
> > >
> >
> >
>
>
>
> --
> Regards,
>
> Deepak
> Oracle DBA
>
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