RE: Check if async_io is enabled at disk-level
- From: "Crisler, Jon" <Jon.Crisler@xxxxxxx>
- To: <sharmakdeep_oracle@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 16 Sep 2008 10:16:25 -0400
Check to see what the setting is for filesystemio_options. If = setall
this should turn on both async i/o and direct i/o. If this is set to
"none" but disk_async_io = true then I don't know what the end result
would be: perhaps filesystemio_options override disk_async_io. Also
make sure you are at a recent Maintenance Pack for AIX as there are some
known issues with Oracle (but I don't know specifically with AIO).
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Deepak Sharma
Sent: Tuesday, September 16, 2008 12:39 AM
To: oracle-l@xxxxxxxxxxxxx
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
Other related posts:
