C Configuring Raw Devices for Oracle Database

This appendix provides additional information about configuring raw devices to deploy Oracle Database with Oracle Real Application Clusters. You must configure raw devices if you do not use Automatic Storage Management (ASM) or an Oracle Cluster File System. The topics in this appendix are:

Support for Raw Devices
Raw Devices Required by Database Configuration Assistant

C.1 Support for Raw Devices

Oracle Database supports the use of raw devices for Oracle files on Windows 2000 and Windows Server 2003. You can partition a raw device to store data and control files. You can also use the entire raw device to store data. You can create partitions on Windows by using the Disk Management utility, Diskmgmt.msc. To access this utility:

Click Start.
Select Run... from the program list.
In the Run dialog box, type diskmgmt.msc.

C.2 Raw Devices Required by Database Configuration Assistant

If you want to use Database Configuration Assistant (DBCA) to create a database on raw storage, that is, without using ASM or an Oracle Cluster File System, then you must configure raw devices as described in this section. These devices are in addition to the OCR and voting disk required to install Oracle Clusterware. Create these devices before running Oracle Universal Installer to install Oracle Database 11g software. DBCA cannot create an Oracle RAC database unless you have properly configured the following devices:

Four raw devices for four tablespace datafiles
At least two raw devices for control files
One raw device for each instance for its own tablespace for automatic undo management
At least two raw devices for redo log files for each instance
One raw device for the server parameter file

Note:
Each instance has its own redo log files, but all instances in a cluster share the control files and datafiles. In addition, each instance's online redo log files must be readable by all other instances to enable recovery.

C.2.1 Planning Your Raw Device Creation Strategy

If you are planing to install Oracle RAC, then before you install, you should create enough partitions of specific sizes to support your database, and also leave a few spare partitions of the same size for future expansion. For example, if you have space on your shared disk array, then select a limited set of standard partition sizes for your entire database. Partition sizes of 100 MB, 500 MB, and 1 GB are suitable for most databases. Also create a few very small and a few very large spare partitions that are, for example, 10 MB and perhaps 5 GB or greater in size. Based on your plans for using each partition, determine the placement of these spare partitions by combining different sizes on one disk, or by segmenting each disk into same-sized partitions.

Note:

Ensuring that there are spare partitions enables you to perform emergency file relocations or additions if a tablespace datafile becomes full.