Check if async_io is enabled at disk-level

From: Deepak Sharma <>
Date: Mon, 15 Sep 2008 21:39:09 -0700 (PDT)
Message-ID: <>


We are using ODM (Oracle Disk Manager) on one of our 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 :

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() ?


Received on Mon Sep 15 2008 - 23:39:09 CDT

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