Hi,
Well, basically it's a mount option that indicates how the OS manages =
the
filesystems. The "default" uses OS buffering.=20
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-----
From: VIVEK_SHARMA [mailto:VIVEK_SHARMA_at_infy.com]
Sent: segunda-feira, 4 de Setembro de 2000 7:48
To: 'PFigueiredo_at_europeantelecom.at'
Cc: 'ORACLE-L_at_fatcity.com'
Subject: RE: Optimal hard disk layout for Oracle
Pedro wrote - "Use forcedirectio on Oracle database devices"
Give more Detail please on forcedirectio .=20
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
>=20
> Hi,
>=20
> I believe Raid 5 is not very recommended with OLTP environments.=20
> If you can use Raid 0 + 1 in a cluster solution it would be the ideal
> solution.
> Do some more research on the subject...
>=20
> 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...
>=20
> Best regards
>=20
> Pedro Figueiredo
>=20
> -----Original Message-----
> Sent: s=E1bado, 2 de Setembro de 2000 1:50
> To: Multiple recipients of list ORACLE-L
>=20
>=20
> 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.
>=20
> _Ernie
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> Sent: Friday, September 01, 2000 6:08 PM
>=20
>=20
> > 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 (e.g. =
place
> > rollback segments or temp tablespace on a separate disk)?
> >
> > Any input would be appreciated.
> >
> > Thanks,
> > Helmut
> >
> > --
> > Author: Helmut Daiminger
> > INET: hdaiminger_at_vivonet.com
> >
> > Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> > San Diego, California -- Public Internet access / Mailing =
Lists
> > =
> > To REMOVE yourself from this mailing list, send an E-Mail message
> > to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> > the message BODY, include a line containing: UNSUB ORACLE-L
> > (or the name of mailing list you want to be removed from). You may
> > also send the HELP command for other information (like =
subscribing).
> >
>=20
> --=20
> Author: Ernest Simard
> INET: simard_at_sonoma.edu
>=20
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing =
Lists
> --------------------------------------------------------------------
> To REMOVE yourself from this mailing list, send an E-Mail message
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> also send the HELP command for other information (like subscribing).
> --=20
> Author: Figueiredo, Pedro
> INET: PFigueiredo_at_europeantelecom.at
>=20
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing =
Lists
> --------------------------------------------------------------------
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Received on Mon Sep 04 2000 - 08:16:19 CDT
