RE: The ill effects of NOT using direct I/O

From: Allen, Brandon <Brandon.Allen_at_OneNeck.com>
Date: Mon, 14 Feb 2011 14:33:32 -0700
Message-ID: <64BAF54438380142A0BF94A23224A31E11FB386529_at_ONEWS06.oneneck.corp>

Yes, Concurrent IO is better than Direct IO on AIX, but there is no need to set cio in the mount options anymore either - filesystemio_options=setall will take care of it in 10g+:

http://download.oracle.com/docs/cd/B19306_01/server.102/b15658/appa_aix.htm#i631245

"With Oracle Database 10g, you can enable Direct I/O and Concurrent I/O on JFS/JFS2 at the file level. You can do this by setting the FILESYSTEMIO_OPTIONS parameter in the server parameter file to setall or directIO. This enables Concurrent I/O on JFS2 and Direct I/O on JFS for all data file I/O. Because the directIO setting disables asynchronous I/O it should normally not be used. As a result of this 10g feature, you can place data files on the same JFS/JFS2 file system as the Oracle home directory and still use Direct I/O or Concurrent I/O for improved performance. As mentioned earlier, you should still place Oracle Database logs on a separate JFS2 file system for optimal performance."

Regards,
Brandon

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Rich Jesse

<snip>

Concurrent IO
<snip>

The option needs to be applied to the mount options.

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Received on Mon Feb 14 2011 - 15:33:32 CST