Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

To undo the previous run of qio_convertdbfiles and change Quick I/O files back to

regular VxFS files

If the database is running, shut it down.

Run the following command from the directory containing the mkqio.dat

file:

$ cd /extract_directory

$ /opt/VRTSdbed/bin/qio_convertdbfiles -u

The list of Quick I/O files in the mkqio.dat file is displayed. For example:

.file1::cdev:vxfs: --> file1

.file2::cdev:vxfs: --> file2

.file3::cdev:vxfs: --> file3

.file4::cdev:vxfs: --> file4

.file5::cdev:vxfs: --> file5

The qio_convertdbfiles command with the undo option (-u) specified

renames the files from <.filename> to <filename> and undoes the symbolic

link to .filename that was created along with the Quick I/O files.

About sparse files

Support for sparse files lets applications store information (in inodes) to identify

data blocks that have only zeroes, so that only blocks containing non-zero data

have to be allocated on disk.

For example, if a file is 10KB, it typically means that there are blocks on disk

covering the whole 10KB. Assume that you always want the first 9K to be zeroes.

The application can go to an offset of 9KB and write 1KB worth of data. Only a

block for the 1KB that was written is allocated, but the size of the file is still 10KB.

The file is now sparse. It has a hole from offset 0 to 9KB. If the application reads

any part of the file within this range, it will see a string of zeroes.

If the application subsequently writes a 1KB block to the file from an offset of

4KB, for example, the file system will allocate another block.

The file then looks like:

■ 0-4KB - hole

■ 4-5KB - data block

■ 5-9KB - hole

■ 9-10KB - data block

Using Veritas Quick I/O

About sparse files