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WARNING:Could not increase the asynch I/O limit to 164 for SQL direct I/O

原创 Linux操作系统 作者:zhouxianwang 时间:2013-09-23 00:02:09 0 删除 编辑
/u01/app/oracle/admin/hanmi/udump/hanmi_ora_27196.trc
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1
System name:    Linux
Node name:    hanmidb.com.cn
Release:    2.6.18-238.9.1.el5
Version:    #1 SMP Tue Apr 12 18:10:13 EDT 2011
Machine:    x86_64
Instance name: hanmi
Redo thread mounted by this instance: 1
Oracle process number: 227
Unix process pid: 27196, image: oracle@hanmidb.com.cn

*** ACTION NAME:() 2013-09-17 15:53:55.047
*** MODULE NAME:(JDBC Thin Client) 2013-09-17 15:53:55.047
*** SERVICE NAME:(SYS$USERS) 2013-09-17 15:53:55.047
*** SESSION ID:(630.42797) 2013-09-17 15:53:55.047
WARNING:Could not increase the asynch I/O limit to 164 for SQL direct I/O. It is set to 128
WARNING:Could not increase the asynch I/O limit to 164 for SQL direct I/O. It is set to 128







Modified:02-Mar-2013Type:PROBLEMStatus:PUBLISHEDPriority:3
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In this Document
  Symptoms
  Cause
  Solution
  References


APPLIES TO:

Oracle Server - Enterprise Edition - Version: 10.2.0.5 and later   [Release: 10.2 and later ]
Generic Linux
disk_asynch_io = TRUE
filesystemio_options = none
[root@xyz ~]# cat /etc/issue
Enterprise Linux Enterprise Linux Server release 5.2 (Carthage)

SYMPTOMS

Using 10.2.0.5 RDBMS on Linux.

The following error occurs in trace files.

ERROR
-----------------------
WARNING:Could not increase the asynch I/O limit to 240 for SQL direct I/O. It is set to 128

CAUSE

aio-max-size is set not set, the default is128


[root@xyz ~]# cat /proc/sys/fs/aio-max-size
cat: /proc/sys/fs/aio-max-size: No such file or directory
[root@xyz ~]# cat /proc/sys/fs/aio-max-nr
65536

SOLUTION

The aio-max-size kernel parameter doesn't exist in the 2.6.x Linux kernels. 
This feature is now "automatic" in the 2.6.x kernel, based on the physical capabilities of the disk device driver.
This should mean that the Linux Kernel is ready to perform. ASYNC I/O.

All install requirements should be met.

To ensure ASYNC I/O can be performed by Oracle Database you need to verify or set the following parameters in the Database:

sql> alter system set disk_asynch_io=true scope=spfile;
sql> alter system set filesystemio_options=setall scope=spfile;

Then shutdown and startup the database and check if the warning reappears.
An HCVE report (refer to Note 250262.1) should report no remaining issues

If the above doesn't resolve the problem, then increase fs.aio-max-nr

REFERENCES

BUG:10334897 - COULD NOT INCREASE THE ASYNCH I/O LIMIT TO NNN FOR SQL DIRECT I/O. IT IS SET TO
BUG:9772888 - WARNING:COULD NOT LOWER THE ASYNCH I/O LIMIT TO 160 FOR SQL DIRECT I/O. IT IS SE
NOTE:205259.1 - Howto Enable Asynchoronous I/O on Red Hat Linux 2.1
NOTE:225751.1 - Asynchronous I/O (aio) on RedHat Advanced Server 2.1 and RedHat Enterprise Linux 3
http://dbaspot.com/forums/sybase/241281-how-set-up-max-io-size-rhel-4-0-a.html

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