答复： Check if async_io is enabled at disk-level

I think what you have seen with nmon just confirms you are using kaio. If it is using threaded aio then the aioserver will be used. Truss should proves that. I am not sure what the system call is like on aix, on solaris it is pwrite vs kaio(write...). Should be somrthing similar

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-----Original Message-----

From: Deepak Sharma <sharmakdeep_oracle_at_yahoo.com>

Date: Mon, 15 Sep 2008 21:39:09
To: <oracle-l_at_freelists.org>
Subject: Check if async_io is enabled at disk-level

Hi,

We are using ODM (Oracle Disk Manager) on one of our 10.2.0.3 DBs, and the disk_asynch_io is TRUE in the database. I have also read that ODM supports kernel asynchronous I/O. The platform is AIX 5.3

Using 'nmon' and choosing "A = Async I/O Servers", this is what we see :

Asynchronous-I/O-Processes
Total AIO processes= 100 Actually in use= 0

This might indicate that AIO is not happening at kernel-level.

How else can we verify if async I/O is actually happening at Kernel-level? We could possibly truss the DB Writer process(es) and check for the kernel-level calls for writes - what should we look for? Is it kiowrite() instead of plain, write() ?

Thanks,
Deepak       

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http://www.freelists.org/webpage/oracle-l Received on Tue Sep 16 2008 - 09:54:34 CDT