RE: AIX 5.2 - JFS2 - CIO/DIO

As others have pointed out, there is no need to mount the filesystems for your *datafiles* with cio - here is the documentation to back it up that claim, along with further recommendation to make sure you _do_ create the filesystems for your _redologs_ with the cio option and with agblksize=512. This is the way I have my 10.2/AIX5.3 system configured and it is working great.

Regards,
Brandon

From
http://download-west.oracle.com/docs/cd/B19306_01/server.102/b15658/appa _aix.htm#i631245:

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Considerations for JFS and JFS2

If you are placing Oracle Database logs on a JFS2 file system, then the optimal configuration is to create the file system using the agblksize=512 option and to mount it with the cio option. This delivers logging performance within a few percentage points of the performance of a raw device.

Before Oracle Database 10g, Direct I/O and Concurrent I/O could not be enabled at the file level on JFS/JFS2. Therefore, the Oracle home directory and data files had to be placed in separate file systems for optimal performance. The Oracle home directory was placed on a file system mounted with default options, with the data files and logs on file systems mounted using the dio or cio options.

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.
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-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Patty.Charlebois_at_greenshield.ca

Does anyone have any experience with AIX 5.2 - JFS2 and recommendations for mounting the filesystems and using CIO/DIO with Oracle 10.2?

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