Oracle RMAN Pocket Reference

RMAN Architecture

Recovery Manager (RMAN) is a utility that can manage all of your Oracle backup and recovery activities. DBAs are often wary of using RMAN because of its perceived complexity and its control over performing critical tasks. The traditional backup and recovery methods are tried-and-true. Thus, when your livelihood depends on your ability to back up and recover the database, why implement a technology like RMAN? The reason is that RMAN comes with several benefits:

• Incremental backups that only copy data blocks that have changed since the last backup.

• Tablespaces are not put in backup mode, thus there is no extra redo log generation during online backups.

• Detection of corrupt blocks during backups.

• Parallelization of I/O operations.

• Automatic logging of all backup and recovery operations.

• Built-in reporting and listing commands.

RMAN’s architecture is a combination of an executable program (the rman utility) and background processes that interact with one or more databases and with I/O devices. There are several key architectural components to be aware of:

• RMAN executable

• Server processes

• Channels

• Target database

• Recovery catalog database (optional)

• Media management layer (optional)

• Backups, backup sets, and backup pieces

The following sections describe each of these components.