Re: Performance difference between 2 machines

Fabrizio wrote:

> disk_async_io? I was referring to OS aio but since we are here:
> disk_async_io is enabled by default on 9i (the OP version).

Yes, but not active! Check out the Metalink stuff on aio:

HPUX: although it is enabled from Oracle, it is not available in HPUX cooked IO. You can only use RAW. And in fact, for ia64 HPUX 11 boxes there is currently a bug with 9ir2 that causes a log dump to be produced in $ORACLE_HOME/rdbms/log every minute! Due to Oracle forcing the use of an unauthorised AIO in HPUX. There is an arcane workaround, but the whole thing is iffy and shaky to start with. DAMHIKT, 150000 log dumps later...

RHAS: you need a number of patches to both RHAS3 and 9ir2 to make aio and dio work even though it is enabled by default in Oracle. In fact, even if you use filesystemio_options=setall, you STILL won't see an strace of open(O_ASYNC) unless you got ALL the patches in there. Same for dIO. This is of course for cooked IO. The situation is slightly better for RHAS4 (kernel 2.6), but 10g is the only one certified there...

Solaris: I strongly suspect Sy is spot on, it only works well in 9ir2 with RAW.

To fix all this mess you can of course invest in Veritas file system and its extensions, but watch your pocket!

I really, really wish Oracle would clean up this TOTAL MESS of cooked aio/dio in 9ir2! Quite frankly, their attitude of only fixing 10g is causing a lot of bad feelings with sites that cannot yet upgrade but need the features NOW. Once again Oracle marketroyds are doing their best to shoot themselves and their product in the foot! Some things never change... Received on Thu Jun 23 2005 - 01:38:21 CDT