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oracle 8.1.6 ioctl error and MLOCK

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Stephanie Nicholls
Frequent Advisor

oracle 8.1.6 ioctl error and MLOCK

Ive just started on a new site and the oracle db's are spitting out the following error approximately 20 times an hour. "Ioctl ASYNC_CONFIG error, errno = 1"

Reading the board indicates this seems to be either a problem with oracle not having access to MLOCK or oracle expecting async io??.

Ive checked my config:
L class servers/hpux 11.00/oracle 8.1.6
databases on raw disk
fs_async is not set in the kernel (set to 0)
no MLOCK privledges for dba

Can I run setprivgrp with oracle running, or do I need to bring down the db's ? (No real test env with oracle on it)

If I set up the MLOCK priv's will I then run into further problems with fs_async? Is Oracle expecting fs_async to be set to 1??

Any comments appreciated.

Vijeesh CTK
Trusted Contributor

Re: oracle 8.1.6 ioctl error and MLOCK


U have to add asyncdsk to kernel and do a setprivgrp to the oracle group.

in my server it is like this
crw-rw-rw- 1 root sys 101 0x000000 Oct 11 2000 async
crw-rw-rw- 1 bin bin 101 0x000000 Oct 11 2000 asyncdsk

setprivgrp "oracle group" MLOCK and u have to restart oracle. then oracle with use async IO. i had a same experience with sybase at my site once.

this link will help u,,0x7e97abe92dabd5118ff10090279cd0f9,00.html,,0xd0b1ba808b46d611abda0090277a778c,00.html


T G Manikandan
Honored Contributor

Re: oracle 8.1.6 ioctl error and MLOCK

I have attached the document from oracle which will resolve your questions.

Stephanie Nicholls
Frequent Advisor

Re: oracle 8.1.6 ioctl error and MLOCK

Thats great info..

On checking my system I have:
initSID.ora set to disk_asynch_io = TRUE
and /dev/async and /dev/asyncdsk created and the correct drivers installed in the kernel.

However MLOCK privs are not set and the system has multiple ora_dbwN processes.

TG: The doco implies that multiple dbwr processes should be used on filesystems not raw devices - is this correct?

Thanks All

T G Manikandan
Honored Contributor

Re: oracle 8.1.6 ioctl error and MLOCK

It is not that Multiple DBWR's cannot be used on raw devices,but oracle does not recommend the use of both multiple DBWr's and aio on raw devices.
As aio cannot be used on a file system, the use of multiple DBWR's is on the file system.

You have to set the MLOCK privilege so that that user ID can use the async driver.

T G Manikandan
Honored Contributor

Re: oracle 8.1.6 ioctl error and MLOCK

Hello steph,
You are right!
When the async i/o is used,
eventhough you set
db_writer_processes to multiple value,only one
DBWR process is started.
async I/O is always preferred over the use of multiple DBWRs.
On older version of Oracle you cannot set multiple DBWR processes when you are using aio.
Recent version start only one DBWR eventhough the parameter is set and you are using aio.