FILESYSTEMIO_OPTIONS-性能优化参数

标签：FILESYSTEMIO_OPTIONS

1. 参数说明

You can use the FILESYSTEMIO_OPTIONS initialization parameter to enable or disable asynchronous I/O or direct I/O on file system files. This parameter is platform-specific and has a default value that is best for a particular platform.

FILESYTEMIO_OPTIONS can be set to one of the following values:

ASYNCH: enable asynchronous I/O on file system files, which has no timing requirement for transmission.

DIRECTIO: enable direct I/O on file system files, which bypasses the buffer cache.

SETALL: enable both asynchronous and direct I/O on file system files.

NONE: disable both asynchronous and direct I/O on file system files.

2. 修改参数

SQL> show parameter filesystemio

NAME                   TYPE        VALUE

------------------------------------ ----------- ------------------------------

filesystemio_options       string      none

SQL>

SQL> alter system set filesystemio_options=setall ;

alter system set filesystemio_options=setall

                 *

ERROR at line 1:

ORA-02095: specified initialization parameter cannot be modified

#文件系统如果出现io问题，建议设置为setall

SQL> alter system set filesystemio_options=setall scope=spfile;

System altered.

SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL> startup

ORACLE instance started.

Total System Global Area  784998400 bytes

Fixed Size                  2217464 bytes

Variable Size             473958920 bytes

Database Buffers          306184192 bytes

Redo Buffers                2637824 bytes

Database mounted.

Database opened.

SQL> show parameter filesystemio_options

NAME                  TYPE        VALUE

------------------------------------ ----------- ------------------------------

filesystemio_options      string      SETALL

SQL>

3. 官方链接

https://docs.oracle.com/cd/E11882_01/server.112/e41573/os.htm#PFGRF94413

FILESYSTEMIO_OPTIONS-性能优化参数

标签：FILESYSTEMIO_OPTIONS

原文地址：http://blog.51cto.com/roidba/2113817