Wilfrid Allembrand wrote:
> Ah ok. So if I understand well, you always need to have AIO configured
> because Oracle use it for its internal mechanisms : it has nothing to
> do with the options (DIO / CIO / raw) you choose to use for your fs
> layout.
> I am right ?
>
> Thank you.

Yep, notice section 15.3.3 of the tuning guide relating to Oracle.

AIO is supported for all jfs type file systems, even raw devices.
Not configuring this is one of the biggest performance mistakes AIX and
Oracle DBA admins make.

If using NMON performance analyzer, the A command will show AIO stats
currently in use, peak use... etc