Veritas Storage Foundation for Oracle 5.0 Administrator's Guide, HP-UX 11i v3, Second Edition, December 2008

contiguous space on the file system, the file is created as a series of direct extents.

Accessing a file using direct extents is inherently faster than accessing the same

data using indirect extents. Internal tests have shown performance degradation

in OLTP throughput when using indirect extent access. In addition, this type of

preallocation causes no fragmentation of the file system.

You must preallocate Quick I/O files because they cannot be extended through

writes using their Quick I/O interfaces. They are initially limited to the maximum

size you specify at the time of creation.

See “Extending a Quick I/O file” on page 94.

About Quick I/O naming conventions

VxFS uses a special naming convention to recognize and access Quick I/O files as

raw character devices. VxFS recognizes the file when you add the following

extension to a file name:

::cdev:vxfs:

Whenever an application opens an existing VxFS file with the extension

::cdev:vxfs: (cdev being an acronym for character device), the file is treated as

if it were a raw device. For example, if the file temp01 is a regular VxFS file, then

an application can access temp01 as a raw character device by opening it with the

name:

.temp01::cdev:vxfs:

Note: We recommend reserving the ::cdev:vxfs: extension only for Quick I/O

files. If you are not using Quick I/O, you could technically create a regular file

with this extension; however, doing so can cause problems if you later enable

Quick I/O.

How to set up Quick I/O

Quick I/O is included in the VxFS package shipped with Veritas Storage Foundation

for Oracle. By default, Quick I/O is enabled when you mount a VxFS file system.

If Quick I/O is not available in the kernel, or the Veritas Storage Foundation for

Oracle license is not installed, a file system mounts without Quick I/O by default,

the Quick I/O file name is treated as a regular file, and no error message is

displayed. If, however, you specify the -o qio option, the mount command prints

the following error message and terminates without mounting the file system.

VxFDD: You don't have a license to run this program

vxfs mount: Quick I/O not available

Using Veritas Quick I/O

About Quick I/O