Converting Oracle Files to Quick I/O Files

Special commands, available in the /opt/VRTSdbed/bin directory, are provided to assist you in converting an existing database to use Quick I/O. You can use the qio_getdbfiles command to extract a list of file names from the database system tables and the qio_convertdbfiles command to convert this list of database files to use Quick I/O.

Prerequisites

• Log in as the Database Administrator (typically, the user ID oracle) to run the qio_getdbfiles and qio_convertdbfiles commands.
• You must predefine the Oracle environment variable $ORACLE_SID.
• The repository must exist before you can convert to Quick I/O files. Run the dbed_update command to update or create the repository.
• Files you want to convert must be regular files on VxFS file systems or links that point to regular VxFS files.

Options

For the qio_getdbfiles command:

For the qio_convertdbfiles command:

Usage Notes

• Converting existing database files to be Quick I/O files may not be the best choice if the files are fragmented. Use the -f option to determine the fragmentation levels and either:
• Exclude files that are highly fragmented and do not have sufficient contiguous extents for Quick I/O use.

or

• Create new files with the qiomkfile command, rather than converting the files using the qio_convertdbfiles command. The new files will be contiguous. You must then move data from the old files to the new files using the dd(1M) command or a database import facility, and then define the new files to the database.
• By default, qio_getdbfiles skips any tablespaces marked TEMPORARY. Tablespaces marked TEMPORARY can be sparse, which means that not all blocks in the file are allocated. Quick I/O files cannot be sparse, as Quick I/O provides a raw-type interface to storage. If a sparse file is converted to a Quick I/O file, the Oracle instance can fail if Oracle attempts to write into one of these unallocated blocks. See Handling Oracle Temporary Tablespaces and Quick I/O for more information.

For information on creating Quick I/O files for temporary tablespaces, see Creating Database Files as Quick I/O Files Using qiomkfile.

• Instead of using the qio_getdbfiles command, you can manually create the mkqio.dat file containing the Oracle database filenames that you want to convert to Quick I/O files.

The qio_convertdbfiles command exits and prints an error message if any of the database files are not on a VxFS file system. If this happens, you must remove any non-VxFS files from the mkqio.dat file before running the qio_convertdbfiles command.

  To extract a list of Oracle files to convert

With the database instance up and running, run the qio_getdbfiles command from a directory for which you have write permission:

The qio_getdbfiles command extracts the list file names from the database system tables and stores the file names and their size in bytes in a file called mkqio.dat under the current directory.

The mkqio.dat list file should look similar to the following:

  To convert the Oracle database files to Quick I/O files

1. Shut down the database.

   ---

    Caution    Running the qio_convertdbfiles command while the database is up and running can cause severe problems with your database, including loss of data, and corruption.

   ---

2. Run the qio_convertdbfiles command from the writable directory where the mkqio.dat list resides:
     $ cd /extract_directory 
     $ /opt/VRTSdbed/bin/qio_convertdbfiles

   The list of files in the mkqio.dat file is displayed. For example:

   
      file1 --> .file1::cdev:vxfs:
      file2 --> .file2::cdev:vxfs:
      file3 --> .file3::cdev:vxfs:
      file4 --> .file4::cdev:vxfs:
      file5 --> .file5::cdev:vxfs:

   Run the qio_convertdbfiles command (with no options specified) to rename the file filename to .filename and creates a symbolic link to .filename with the Quick I/O extension. By default, the symbolic link uses a relative path name.

   The qio_convertdbfiles script exits and prints an error message if any of the database files are not on a VxFS file system. If this happens, you must remove any non-VxFS files from the mkqio.dat file before running the qio_convertdbfiles command again.

3. Start up the database.

   You can now access these database files using the Quick I/O interface.

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

1. If the database is running, shut it down
2. Run the following command from the writable directory where the mkqio.dat list resides:
     $ 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.