Converting from raw devices <a class="indexterm" name="id435810"></a>


Converting from raw devices
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Converting from raw devices

If the database is currently using raw disks or volumes, use one of the following procedures to use VxFS with the Quick I/O feature or Oracle Disk Manager.

Warning:

The procedure provided assumes that the database runs on a single file system after the upgrade.

To convert from raw devices to VxFS with Quick I/O

Create a VxFS file system using a size that is 10 percent larger than the original database or total raw device size. You can create more file systems based on your performance and availability requirements.

See Creating a VxFS file system .
Shut down the database.
Preallocate Quick I/O files using qiomkfile.

See Creating database files as Quick I/O files using qiomkfile.
Copy each raw device file to the new VxFS file system.

For example, use the dd command to copy the file /dev/rdsk/Disk_2 to /db01/dbfile:
```
$ dd if=/dev/rdsk/Disk_2 of=/db01/dbfile ibs=4k skip=1 obs=128k
```
If the database uses symbolic links to access the database files, change the symbolic links to point to the Quick I/O files.

For example, if the database has a datafile specification /data/file1 that was linked to /dev/rdsk/Disk_2, change it to point to the new Quick I/O file:
```
  $ rm /data/file1
  $ ln -s /db01/dbfile /data/file1 
```
If the database was using absolute paths to access the database files, rename each file within Oracle before bringing the database online. For example:
```
  $ sqlplus "/ as sysdba"

		SQL> startup mount;
		SQL> alter database rename file filename to newfilename;
```
Restart the database. For example:
```
  SQL> alter database open;
		SQL> exit
```

To convert from raw devices to regular files for ODM

Create a VxFS file system using a size that is 10 percent larger than the original database or total raw device size. You can create more file systems based on your performance and availability requirements.

See Creating a VxFS file system .
Shut down the database.
Preallocate the files for ODM using odmmkfile.
```
odmmkfile -h header_size -s file_size filename
```
where -h creates a file with additional space allocated for the Oracle header and -s preallocates a certain amount of space for the file.
Copy each raw device file to the new VxFS file system.

For example, use the dd command to copy the file /dev/rdsk/Disk_2 to /db01/dbfile:
```
$ dd if=/dev/rdsk/Disk_2 of=/db01/dbfile ibs=4k skip=1 obs=128k
```
If the database uses symbolic links to access the database files, change the symbolic links to point to the new files.

For example, if the database has a datafile specification /data/file1 that was linked to /dev/rdsk/Disk_2, change it to point to the new file:
```
$ rm /data/file1
		$ ln -s /db01/dbfile /data/file1 
```
If the database was using absolute paths to access the database files, rename each file within Oracle before bringing the database online. For example:
```
$ sqlplus "/ as sysdba"
		SQL> startup mount;
		SQL> alter database rename file filename to newfilename;
```
Restart the database. For example:
```
SQL> alter database open;
		SQL> exit
```

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