VERITAS File SystemÖ 3.5 (HP OnlineJFS/JFS3.5) AdministratorÆs Guide (December 2002)

Chapter 8

Quick I/O for Databases

Creating a Quick I/O File Using qiomkfile

The best way to make regular files accessible to the Quick I/O interface and preallocate space for them is to

use the qiomkfile command. Unlike the VxFS setext command, which requires superuser privileges, any user

who has read/write permissions can run qiomkfile to create the files. The qiomkfile command has five options:

You can specify file size in terms of bytes (the default), or in kilobytes, megabytes, gigabytes, or sectors (512

bytes) by adding a k, K, m, M, g, G, s or S suffix. If the size of the file including the header is not a multiple of

the file system block size, it is rounded to a multiple of the file system block size before preallocation.

qiomkfile creates two files: a regular file with preallocated, contiguous space; and a symbolic link pointing to

the Quick I/O name extension. For example, to create a 100 MB file named dbfile in /database, enter:

$ qiomkfile -s 100m /database/dbfile

In this example, the first file created is a regular file named /database/.dbfile (which has the real space

allocated).

The second file is a symbolic link named /database/dbfile. This is a relative link to /database/.dbfile

via the Quick I/O interface, that is, to .dbfile::cdev:vxfs:. This allows .dbfile to be accessed by any

database or application as a raw character device. To check the results, enter:

$ ls -al

-rw-r--r-- 1 oracle dba 104857600 Oct 22 15:03 .dbfile

lrwxrwxrwx 1 oracle dba 19 Oct 22 15:03 dbfile -> \

.dbfile::cdev:vxfs:

or:

$ ls -lL

crw-r----- 1oracle dba 43,0 Oct 22 15:04 dbfile

-rw-r--r-- 1oracle dba 10485760 Oct 22 15:04 .dbfile

If you specify the -a option to qiomkfile, an absolute path name (see “Using Absolute or Relative Path

Names” on page 81) is used so /database/dbfile points to /database/.dbfile::cdev:vxfs:. To check the

results, enter:

$ ls -al

-rw-r--r-- 1 oracle dba 104857600 Oct 22 15:05 .dbfile

lrwxrwxrwx 1 oracle dba 31 Oct 22 15:05 dbfile ->

/database/.dbfile::cdev:vxfs:

See the qiomkfile (1) manual page for more information.

-a Creates a symbolic link with an absolute path name for a specified

file. The default is to create a symbolic link with a relative path name.

-e (For Oracle database files to allow tablespace resizing.) Extends the

file size by the specified amount.

-h (For Oracle database files.) Creates a file with additional space

allocated for the Oracle header.

-r (For Oracle database files to allow tablespace resizing.) Increases the

file to the specified size.

-s Preallocates space for a file.