RE: Using Direct I/O Filesystem for Oracle Database

From: <>
Date: Wed, 9 Jan 2008 11:13:56 -0700
Message-ID: <002401c852eb$6793c9b0$6401a8c0@BHAIRAVIPC01>

Muhammad Salman Faheem,  

You should read, if you have not already, Steve Adam's works in ixora
( <> ) for async io and
direct io and Oracle internals, and also Cary Millsap's works in hotsos
( that deals with the proportionality of the effect on change
As Dave said have benchmarks and baselines that allow you to establish and measure change.  


From: [] On Behalf Of Junior DBA
Sent: Tuesday, January 08, 2008 10:41 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 - 12:13:56 CST

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