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Oracle async_config errno=11

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Ronnie Doggart
Frequent Advisor

Oracle async_config errno=11

Hi,

We are running Oracle 9.2.0.4 on an Itanium box with HP-UX 11.23. The database appears to be running OK but I am getting lots of trace files generated each day which state:

Ioctl ASYNC_CONFIG error, errno = 11

Does anyone have any idea what is causing this?

Ronnie

9 REPLIES
RAC_1
Honored Contributor

Re: Oracle async_config errno=11

Never worked on that, but should be same as that of PA-RISC servers.

Do you have /etc/privgroup file? IT should have following entry.

dba MLOCK

Where dba is group which runs oracle. If not do setprivgrp dba MLOCK.

Also you should have /dev/async device file with appropriate rights.

And lock_sga' set to true in the Oracle init file

Anil
There is no substitute to HARDWORK
Navin Bhat_2
Trusted Contributor

Re: Oracle async_config errno=11

Could also post the any other error messages that were accompanied with this error?
Hein van den Heuvel
Honored Contributor
Solution

Re: Oracle async_config errno=11

You did want /dev/async IO with disk_asynch_io=1 in init.ora right?

As Anil wrote, lack of MLOCK priv could be one reason for failure.

You are using RAW devices right?
If you are using regular filesystems for their Oracle database, they'll get this error due to a bug in Oracle. It does not have any performance impact, but if they want to get rid of the messages, they should just rename /dev/async, so that Oracle does not find that device at all. (you do have a /dec/async no?)

If you're out of lockable_mem, that's another reason.

Check metalink for more input on async and this error.

Hein
Ronnie Doggart
Frequent Advisor

Re: Oracle async_config errno=11

Hi All,

And thanks for the responses. I already have the dba mlock set and checked. The asynch_disk_io = false in the init.ora since we are using filesystems. There are no other errors in the trace files. I will try setting lock_sga and see if that helps.

Ronnie
Hein van den Heuvel
Honored Contributor

Re: Oracle async_config errno=11

Sounds like you hit that bug and may have to rename (mv) /dev/async to hide it from Oracle. Not sure whether that woudl be needed during startup only or all the time.
Does any other app in your systems need /dev/async?

Hein.

Re: Oracle async_config errno=11

I have had the same problem with Veritas Database Edition for Oracle. This product allows you to do async IO to filesystems. No need for raw devices.

To fix error the problem,
- setprivgrp dba MLOCK
- setprivgrp oracle MLOCK
- setprivgrp oinstMLOCK

Where oinst is the install user and dba and oracle are the groups for the connecting processes. Need all entries.

I noticed the IO profile changed straight away (vxstat).

I do have a question. Does the error mean that oracle has switch off async-io ? I did see the io profile change but I did not see any performance gain.

Viktor
Hein van den Heuvel
Honored Contributor

Re: Oracle async_config errno=11


Just rambling...

The benefits of Async IO are marginal for your average Oracle solution. Improvements are in the order of 1 - 3% cpu time (system) for systems that do 100% Oracle work and are relatively heavy on the IO (think TPC). Toss some real applicition code in the mix and make Oracle do a little more parsing and computing and the benefit becomes really small.
You will need a very reproducable test to prove a benefit expressed in % cpu or response time. Next best are observations like Viktor's where an IO pattern change is seen. For example you might notice that the File-system pre-reads for REDOLOG io dissappears, leaving only writes. An other alternative is to normalize (system) cpu usage with business transactions. How much cpu per 1000 transactions? Did that change before/after Async was activated? And finally, you could run an application test before adn after. But typically a reproducable tests is not terribly repersentative of real life.

In my mind the biggest benefits of RAW devices and Async IO are knowing that as a DBA you did everthing you could possibly do to optimize the system.


Hein.
Ronnie Doggart
Frequent Advisor

Re: Oracle async_config errno=11

Many thanks to you all, I had to m0ve /dev/async out of the way to stop Oracle producing the error.
Evren Atasayar
Occasional Visitor

Re: Oracle async_config errno=11

Hi,
I have the same problem, but although I try to set MLOCK with
#setprivgrp dba MLOCK
it does not give the MLOCK privilige.
When I check this by
#getprivgrp dba
it gives:
dba:
What can cause not giving the MLOCK privilige?
Thanks..
Evren