I think you need to be at least on RHEL4 before you can do both Async and Direct I/O. I think with RHEL3 you could do async or direct I/O but not both together. It has been a few years since I ran 9.2 on RHEL3 so I'm not 100% sure this is correct. On Wed, Sep 23, 2009 at 9:38 AM, Niall Litchfield < niall.litchfield@xxxxxxxxx> wrote: > cast your mind back if you will to 9.2.0.7 (after 9.2.0.4 anyway) and Linux > with 2.4 kernel series (RH3 in this case). I know that Oracle supports ASYNC > io and Direct IO on this platform for this version. (and what patches and > incantations were required to make async io work). This article > http://www.labs.redhat.com/magazine/013nov05/features/oracle/ seems > however to suggest that it was only in 10g that we were able to use both > together. I'm not sure I believe it, despite the source, but does anyone > know/recall any restrictions on using both async and direct io together on > that sort of platform at that time. > > -- > Niall Litchfield > Oracle DBA > http://www.orawin.info >