RE: WARNING:io_submit failed due to kernel limitations MAXAIO for process=128 pending aio=127
- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxx>
- To: "sanjeevorcle@xxxxxxxxx" <sanjeevorcle@xxxxxxxxx>, ORACLE-L <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 8 Jun 2011 16:49:07 -0400
Hi Sanjeev,
Are you also seeing 'asynch descriptor resize' wait events?
Tanel talks about this wait event, here:
http://blog.tanelpoder.com/2010/11/23/asynch-descriptor-resize-wait-event-in-oracle/
As to tuning kernel parameters, well, the error itself lists MAXAIO.
Unfortunately, the actual tunable kernel parameter is not called 'MAXAIO'.
It's 'fs.aio-max-nr', and can be set in /etc/sysctl.conf.
What, if anything, do you have for 'fs.aio-max-nr' in your /etc/sysctl.conf?
What does Oracle recommend for your 12.1.2 installation? (It may be different
than default value for 11.1.0.7.6 database.)
Looking at one of my RAC nodes, running 11.2.0.2.0, I have it set to 3145728.
Anyhow, hope this helps you understand a bit more about aysnch I/O, the MAXAIO
limit, and the 'asynch descriptor resize' wait event.
-Mark
PS There's also MOS Doc ID 1081977.1, which Tanel mentions in his blog entry,
but, there's not much info there.
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Sanjeev M
Sent: Wednesday, June 08, 2011 4:31 PM
To: ORACLE-L
Subject: WARNING:io_submit failed due to kernel limitations MAXAIO for
process=128 pending aio=127
Gurus,
We have recently moved from Solaris to Linux for our 12.1.2 E-business suite
environment, RDBMS(11.1.0.7.6), GRID/ASM(11.2.0.2) and are observing following
warnings in rdbms trace files:
WARNING:io_submit failed due to kernel limitations MAXAIO for process=128
pending aio=127
Noticed that the module information in the trace files varies from job queue
process,parallel query slave and httpd sessions.
Did search for this error in MOS and got few hits but did not have an exact
match of our situation, raised SR with oracle support.
Have any of you guys encountered these warnings and know what OS parameter to
change to fix this and any recommendation or criteria for setting value for
maxaio.
disk_asynch_io has been set to TRUE.
Regards,
Sanjeev.
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