RE: Optimal hard disk layout for Oracle -

Hi,

We're using SunOS 5.6, VxVA Version 2.6, Solaris Patch-Level 105181-20, Oracle 8.1.5.1.0, Veritas 3.0.3.

Maybe you can have a problem with your Veritas version (seems very old). I would advise you to check with Oracle and Sun Support about this, before trying anything.

The machine where we have it is running a billing system. We had about 20% improvement after changing to directio and a write parameter on devices from 4K to 8K.
I'm not completely aware of this second thing so I can't give detailed information (we had a Sun guy here changing it).

No special precautions that I know of. Basically we had good results and no bad experiences.

Hope this helps. Cheers

Pedro Figueiredo

-----Original Message-----
From: VIVEK_SHARMA [mailto:VIVEK_SHARMA_at_infy.com] Sent: quarta-feira, 13 de Setembro de 2000 12:21 To: 'PFigueiredo_at_europeantelecom.at'; 'kaygopal_at_yahoo.com' Cc: 'ORACLE-L_at_fatcity.com'; 'oracledba_at_quickdoc.co.uk' Subject: Optimal hard disk layout for Oracle -

Pedro, Gopal , List

A Few more please

Does Enabling it require any SUN OS / Veritas / Oracle Patches ?

NOTE - Existing Setup Details for which forcedirectio is being considered is :-
SunOS 5.6 , Oracle 7.3.4.5 , Veritas Version 1.1.2 Transactions here Primarily OLTP in nature .

Any Rough Estimate of Percentage Performance Benefit you Experienced with this Set ?

Are there any PRECAUTIONS / must dos / don'ts ? for this is a Live Database where Almost NO Downtime can be Afforded

Thanks Again

-----Original Message-----

From:	Figueiredo, Pedro [SMTP:PFigueiredo_at_europeantelecom.at]
Sent:	Tuesday, September 12, 2000 2:21 PM
To:	Multiple recipients of list ORACLE-L
Subject:	RE: Optimal hard disk layout for Oracle

Hi,

We have it on a Veritas Cluster. It's not a problem. The parameter on vfstab is 'forcedirectio'.
No ideas for Digital Unix.

Bye

Pedro Figueiredo

-----Original Message-----
Sent: quinta-feira, 7 de Setembro de 2000 14:28 To: 'PFigueiredo_at_europeantelecom.at'; 'kaygopal_at_yahoo.com' Cc: 'ORACLE-L_at_fatcity.com'; 'oracledba_at_quickdoc.co.uk'

For SUN OS Can it be Enabled for Mounted Partitions on a Veritas Cluster ? Any Detail on the Corresponding O.S. parameter in /etc/vfstab ?

Thanks again

> -----Original Message-----
> From: VIVEK_SHARMA
> Sent: Wednesday, September 06, 2000 11:56 AM
> To: 'PFigueiredo_at_europeantelecom.at'; 'kaygopal_at_yahoo.com'
> Cc: 'ORACLE-L_at_fatcity.com'; 'oracledba_at_quickdoc.co.uk'
> Subject: RE: Optimal hard disk layout for Oracle
>
>
> Any info on what COMMANDS , parameters Values , switches to use for
> Enabling it
> on Compaq Tru 64 UNIX (Digital Unix) ver 4.0 G ?
>
>
> -----Original Message-----
> From: K Gopalakrishnan [SMTP:kaygopal_at_yahoo.com]
> Sent: Monday, September 04, 2000 1:39 PM
> To: Multiple recipients of list ORACLE-L
> Subject: Re: Optimal hard disk layout for Oracle
>
> Hi !
>
> Basically 'forcedirectio' bypasses the OS buffer cache and
> talks directly to the disk. This increases the performance since
> there is no 'middle man' during the IO.
>
> This is HIGHLY recommended for redo logs.
> In this case the OS buffer cahce is bypassed.
>
> Regards,
> K Gopalakrishnan
> Bangalore, INDIA
>
>
> -----Original Message-----
> From: Figueiredo, Pedro [SMTP:PFigueiredo_at_europeantelecom.at]
> Sent: Monday, September 04, 2000 5:50 PM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Optimal hard disk layout for Oracle
>
> Hi,
>
> Well, basically it's a mount option that indicates how the OS
> manages the
> filesystems. The "default" uses OS buffering.
> If you specify direct IO, Oracle will perform a most direct device
> access as
> you don't have two layers of buffering.
> This redundacy consumes unecessary OS resources and will delay write
> access.
>
> The file system configuration on Sun Solaris is in /etc/vfstab.
>
> Don't use it on regular mount points. It's completely unnapropriate
> for
> normal I/O operations.
>
> Cheers
>
> Pedro Figueiredo
>
> -----Original Message-----
> Sent: segunda-feira, 4 de Setembro de 2000 7:48
> To: 'PFigueiredo_at_europeantelecom.at'
> Cc: 'ORACLE-L_at_fatcity.com'
>
>
>
> Pedro wrote - "Use forcedirectio on Oracle database devices"
> Give more Detail please on forcedirectio .
> Novice on O.S. here
>
>
> > -----Original Message-----
> > From: Figueiredo, Pedro [SMTP:PFigueiredo_at_europeantelecom.at]
> > Sent: Saturday, September 02, 2000 8:05 AM
> > To: Multiple recipients of list ORACLE-L
> > Subject: RE: Optimal hard disk layout for Oracle
> >
> > Hi,
> >
> > I believe Raid 5 is not very recommended with OLTP environments.
> > If you can use Raid 0 + 1 in a cluster solution it would be the
> ideal
> > solution.
> > Do some more research on the subject...
> >
> > If you have the possibility, use raw devices (at least) for the
> redo log
> > files.
> > Use forcedirectio on Oracle database devices (Sun Solaris
> terminology,
> > other
> > platforms should have similar possibility). No need to have both
> Oracle
> > and
> > OS buffering disk writes...
> >
> > Best regards
> >
> > Pedro Figueiredo
> >
> > -----Original Message-----
> > Sent: sabado, 2 de Setembro de 2000 1:50
> > To: Multiple recipients of list ORACLE-L
> >
> >
> > Hi,
> > Since Temp and Rollbacks are almost all writes you may want to put
> them on
> > a
> > mirror set rather than Raid 5. There is a bit of a write penalty
> but not
> > a
> > major one.
> >
> > _Ernie
> > ----- Original Message -----
> > To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> > Sent: Friday, September 01, 2000 6:08 PM
> >
> >
> > > Hi!
> > >
> > > We are about to get a new database server and my supervisor
> wants me to
> > > specify the hard disk layout. It is a given that we wanna go
> with RAID
> > 5.
> > So
> > > here is what I'm thinking about:
> > >
> > > Disk 1: Operating system + Oracle software
> > > Disk 2: Online Redo Logs
> > > Disk 3: Online Redo logs (mirrored)
> > > Disk 4: archived redo logs
> > > Disk 5-8: Oracle data files (i.e data + index tablespaces, temp
> > tablespaces,
> > > rollback segments)
> > >
> > > Disks 1-4 will be 'stand-alone' disks (i.e. no RAID or
> mirroring). Disks
> > 5-8
> > > will be in a RAID 5 array.
> > >
> > > Do you think it would be beneficial to add like another disk
Received on Wed Sep 13 2000 - 08:29:20 CDT