| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Mailing Lists -> Oracle-L -> RE: Linux RAC and asynch io - OCFS & "filesystemio_options" parameter?
Confiliting info/dates:
My config;
9205
ocfs 1.0.13-1
Anyone want to take a guess as to what "filesystemio_options" should be set to?
Could find a direct answer on Metalink...I would guess
"filesystemio_options=3Dasynch",
because my (Cluster) filesystem supports async IO?
PS I found no posted issues regarding database crashes, Linux & async I/O!?
Chris Marquez
Oracle DBA
HEYMONitor(tm) - heymonitor.com
"Oracle Monitoring & Alerting Solution"
FUL NOTE DEATAILS
Doc ID: Note:252331.1 Subject: Update on OCFS for Linux Last Revision Date: 16-APR-2004
Support for Async IO.
as of ocfs 1.0.9-4 ocfs as a filesystem supports async io functionality.
However, the oracle rdbms code disables asyncio, even when linked in.
There is a patch in the works that can be applied on top of 9.2.0.4 to
re-enable async io on ocfs.
This first needs to go through a round of testing.
Doc ID: Note:240575.1 Subject: RAC on Linux Best Practices Last Revision Date: 03-MAY-2004 ? Using Asynchronous I/O
To enable asynchronous I/O for Oracle9iR2 on Red Hat Linux Advanced
Server 2.1 and
United Linux 1.0 you must re-link Oracle using the Async I/O library,
libaio, as follows:
cd to $ORACLE_HOME/rdbms/lib
make -f ins_rdbms.mk async_on
make -f ins_rdbms.mk ioracle
Two parameters in the init.ora need to be changed, add following lines
to the appropriate init.ora file:
---Parameter settings in init.ora for raw devices:
disk_asynch_io=3Dtrue (default value is true)
---Parameter settings in init.ora file or spfile.ora for filesystem
files:
Make sure that all Oracle datafiles reside on filesystems that support
asynchronous I/O. (For example, ext2, ext3)
disk_asynch_io=3Dtrue (default value is true)
filesystemio_options=3Dasynch
To get better I/O throughput:
For DSS workloads, the /proc/sys/fs/aio-max-size has to be increased
from the default 131072 bytes to >=3D1M.
For OLTP workloads, the default size of 131072 would suffice, as these
workloads perform very small writes.
You can set this value by executing the following command as root user:
echo >/proc/sys/fs/aio-max-size 1048576
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Marquez, Chris
Sent: Friday, January 14, 2005 1:50 PM
To: thump_at_cosmiccooler.org
Cc: oracle-l_at_freelists.org
Subject: RE: Linux RAC and asynch io/IO slaves
David,
Thanks for the info...I going to check metalink too, but go relink sometime today and run some laod tests.
Chris Marquez
Oracle DBA
HEYMONitor(tm) - heymonitor.com
"Oracle Monitoring & Alerting Solution"
-----Original Message-----
From: delysid_at_amber.monochrome.net [mailto:delysid_at_amber.monochrome.net]
On Behalf Of David
Sent: Friday, January 14, 2005 1:05 PM
To: thump_at_cosmiccooler.org
Cc: Marquez, Chris; matthewp_at_amazon.com; oracle-l_at_freelists.org
Subject: RE: Linux RAC and asynch io/IO slaves
Everything I have read advocates aio on RHAS 3.0.
I have heard also it can cause crashes and corruption, but found no meat to that statement no open bugs for 9205/9206 on rhas 3.0 Anyone with any hard facts as to real issues or successes? Anyone done an IO slave implementation in Linux/RAC? IO slaves in many ways are more robust and multi purpose than asych IO functionality...but I'm wondering how that performs with RAC.
Yes, I would and will test either or both before consideration with prod, but looking for others insights if they have been down the road.
-- .. David >> >> Matthew, >> >>>>bugs related to 9i RAC on Linux and asynch io >> >> Can you point to any (bugs) specifically or should I just search=3D20 = >> Metalink? >> >> I was considering enabling this for my 9iRAC/RHEL3ES...Oracle=3D20=20 >> (marketing, presentations) imply that I should be doing this. Frankly >> Oracle Corp. takes much credit for helping RH/Linux get to async-IO? >> >> Thanks, >> >> Chris Marquez >> Oracle DBA >> HEYMONitor(tm) - heymonitor.com >> "Oracle Monitoring & Alerting Solution" -- http://www.freelists.org/webpage/oracle-l -- http://www.freelists.org/webpage/oracle-lReceived on Fri Jan 14 2005 - 14:01:18 CST
 |
 |