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filesystemio_options=asynch
This parameter is platform specific. By default, this parameter is set to none for Linux and thus needs
to be changed:
SQL> show parameter filesystemio_options;
NAME
------------------------------------ ----------- -----------
filesystemio_options
SQL>
The filesystemio_options can have the following values with Oracle9iR2:
• asynch: This value enables asynchronous I/O on file system files.
• directio: This value enables direct I/O on file system files.
• setall: This value enables both asynchronous and direct I/O on file system files.
• none: This value disables both asynchronous and direct I/O on file system files.
If you also want to enable Direct I/O Support which is available in Red Hat Enterprise Linux 4 or 5, set
filesystemio_options to "setall".
In Red Hat Enterprise Linux 3
It is recommended you use direct I/O ONLY for ext2, ext3, GFS, NFS and OCFS file
systems.
In Red Hat Enterprise Linux 4 and 5
It is strongly recommended to use the "setall" parameter for ext2, ext3, GFS, NFS and
OCFS file systems.
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.
Note
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
131072
To change the maximum number of bytes without reboot:
Tuning Asynchronous I/O for Oracle 9i and 10g
TYPE
VALUE
string
none
33
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