CIO on AIX

Hi All,
we have Oracle 9.2.0.6 64-bit database on AIX 5300-03 64 bit.

File systems for data files and redo logs mounted with cio and filesystemio_options set to async (by default for Oracle 9.2.0.6 on AIX).
According to the note "Direct I/O or Concurrent I/O on AIX 5L (272520.1)" under such conditions only asynchronous mode will be used for the database. And to get CIO mode for file system filesystemio_options should be set to SETALL.

But using lsof +fg command
(there was a topic on oracle-l forum about CIO on AIX) I see that datafiles were opened with the following flags "R,W,DSYN,LG,0×80;CX,BR". From the post on http://unix.derkeiler.com/Mailing-Lists/AIX-L/2005-01/0013.html a guy stated that 0×80 flag is the definition
of CIO mode.

At the same time using truss upon checkpoint process I can not find any open() subroutine that uses O_CIO flag.

At the same time, based on the document provided from IBM / Oracle International Competency Center
Oracle 9i & 10g on IBM AIX5L:
Tips & Considerations
Version 2.1
September, 2005
table on a page 8 - in case of ASYNC parameter and file system mounted with cio there will be "asynchronous, CIO" mode. Does anybody know how definitely define if CIO is used or not? And what setting and mount options should be used?

Regards,
Andrey Goryunov

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