VERITAS File System 4.1 Administrator's Guide

Quick I/O for Databases
Creating a Quick I/O File Using qiomkfile
Chapter 11166
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:
-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 Extends the file size by the specified amount.(For Oracle database files to
allow tablespace resizing.)
-h Creates a file with additional space allocated for the Oracle header.(For
Oracle database files.)
-r Creates a file with additional space allocated for the Oracle header.(For
Oracle database files.)
-s Preallocates space for a file.
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 file system block size, it is rounded to a multiple of
the file system block size before preallocation.
The qiomkfile command 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 (whichhas
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: