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12.4. Tuning Asynchronous I/O for Oracle 9i and 10g

For Red Hat Enterprise Linux 3 it is recommended to set aio-max-size to 1048576 since Oracle uses I/Os of up to 1MB. It controls the maximum I/O size for asynchronous I/Os.


The aio-max-size tuning parameter is not applicable to the 2.6 kernel on Red Hat Enterprise Linux 4 or 5.
To determine the maximum I/O size in bytes, execute:
$ cat /proc/sys/fs/aio-max-size
To change the maximum number of bytes without reboot:
# echo 1048576 > /proc/sys/fs/aio-max-size
Alternatively, you can use sysctl(8) to change it:
# sysctl -w fs.aio-max-size=1048576
To make the change permanent, add the following line to the /etc/sysctl.conf file. This file is used during the boot process:
$ echo "fs.aio-max-size=1048576" >> /etc/sysctl.conf