Use bare devices to improve performance of Oracle databases

You need to know the fact that disk I/O is an important reason to affect Oracle database performance. In essence, any Oracle database is responsible for storing data, and querying data from disk is a very expensive and time-consuming operation.

Because many Oracle systems require a large amount of I/O operations, many Oracle professionals consider using the raw device when they encounter large chunks (db_block_size) of data operations. A bare device is a disk that bypasses Unix's Journal filesystem (Journal file System, JFS) for direct access, which eliminates the cost of JFS file system.

The reduction in disk I/O overhead can increase disk throughput, but this is true only if I/O operations are indeed bottlenecks that affect Oracle database performance improvements. In addition, the use of raw devices requires Oracle Administrators and system administrators to do a lot of manual labor.

Oracle recommends that the use of raw devices be considered only when Oracle database performance is subject to I/O speed limits. For such an Oracle database, raw devices can greatly improve overall performance. However, if database performance is not subject to I/O speed constraints, the use of raw devices does not help improve performance.

It is also important to note that in Oracle 8.1.7, this feature is called direct I/O, and some high-end UNIX platforms support this feature. The Veritas company also sells a product called Quick I/O, which provides Oracle with the overhead of being close to the bare device without the need for additional management of the bare devices.