FILESYSTEMIO_OPTIONS Initialization Parameter

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. It can be
dynamically changed to update the default setting.
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.

See Also: Your platform-specific documentation for more details