Re: Asynchronous I/O and AIX and jfs = perf ?

kshave_at_health.gov.mb.ca wrote:

> I had the same question as Doug and I received this information from
> Oracle tech support ...
>
> "Unlike some other unix platforms where Asynchronous I/O is only
> applicable to raw devices on AIX systems it is applicable to datafiles
> on both Unix File systemsand Raw Devices. AS such Asynchronous I/O
> *MUST* be "available for an oracle instance to run properly. If you do
> NOT have async i/o configured, undefined symbols such as "kaio_rdwr,
> iosuspend, acancel..." etc. will be flagged during relinking the rdbms.
> Async I/O is configured by running the root pre.sh script found inthe
> $ORACLE_HOME/orainst directory. If ct wants to take advantage of AIO
> for Oracle he must set USE_ASYNC_IO=TRUE"
>
> The only concern should be note:73397.1 which describes a possible
> problem with async i/o and jfs.
>
> -Keith

<snip>

Make sure you have the latest IBM patches, and upgrade to 4.3.3 asap. IBM resolved quite a few (performance related) issues (bugs?) in this release, especially in the aio server.
AIX 4.3.3.2 is the latest I know of.

BTW your journalling can be a bottleneck, especially when you journal to one disk (which I've seen happening). Also, read consistency checking may have a great (negative) impact. You could consider turning that off, but that is a matter of risk calculation I cannot judge. --
Met vriendelijke groet/kind regards,

Frank van Bortel
Technical consultant Oracle Received on Wed Jan 05 2000 - 12:02:16 CST