RE: Using Direct I/O Filesystem for Oracle Database

From: Herring Dave - dherri <>
Date: Wed, 9 Jan 2008 10:30:53 -0600
Message-ID: <>

Muhammad Salman Faheem,

As with any changes made to address a performance problem, make sure you have a way to measure the effect of the change. You must have a query or two that are existing issues, so use those queries with Oracle stats and waits to show differences before / after the change. Then you'll know for sure the impact of the change you made.


Dave Herring |   A c x i o m   M I C S / C S O 630-944-4762 office | 630-430-5988 wireless | 630-944-4898 fax

From: [] On Behalf Of Junior DBA Sent: Tuesday, January 08, 2008 11:41 PM To:
Subject: Using Direct I/O Filesystem for Oracle Database


Hi All,

We are running Oracle 10g R1 on Sun SPARC Solaris 9 Sun Fire V890 Server.

By default we have following setting in the Database:

disk_asynch_io = TRUE
filesystemio_options= asynch &
dbwr_io_slaves =0

To improve Disk I/O Performance We re-mount Oracle Database FileSystems [ containing Datafiles,logfiles & archive logs] with forcedirectio,noatime option.

After remounting the Oracle Filesystems with forcedirectio,noatime i changed the filesystemio_options to setall i.e.


(1) I need to know if i missed something or made any mistake.

(2) Do i need to change dbwr_io_slaves  or db_writer_processes values

(3) What else i could do to improve DISK I/O performance

Appreciate your valuable feedback.

Best Regards,

Your DBA Colleague
Muhammad Salman Faheem

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Received on Wed Jan 09 2008 - 10:30:53 CST

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