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RMAN client

The client application that manages backup and recovery operations for a target database. The RMAN client can use Oracle Net to connect to a target database, so it can be located on any host that is connected to the target host through Oracle Net.

Target Database

A database containing the control files, datafiles, and optional archived redo logs that RMAN backs up or restores. RMAN uses the target database control file to gather metadata about the target database and to store information about its own operations. The work of backup and recovery is performed by server sessions running on the target database.

The only required components in an RMAN environment are a target database and RMAN client, but most real-world configurations are more complicated.

RMAN Command-Line Client

Use the RMAN command-line client to enter commands that you can use to manage all aspects of backup and recovery operations. RMAN uses a command language interpreter that can execute commands in interactive or batch mode. Even when you use the backup and recovery features in Enterprise Manager that are built on top of RMAN, an RMAN client executes behind the scenes.

RMAN Channels

The RMAN client directs database server sessions to perform all backup and recovery tasks. What constitutes a session depends on the operating system.

The RMAN client itself does not perform backup, restore, or recovery operations. When you connect the RMAN client to a target database, RMAN allocates server sessions on the target instance and directs them to perform the operations.

An RMAN channel represents one stream of data to a device, and corresponds to one database server session. The channel reads data into memory, prosesses it, and writes it to the output device.

Most RMAN commands are executed by channels, which must be either configured to persist across RMAN sessions, or manually allocated in each RMAN session.

Entering RMAN Commands at the RMAN Prompt

Most RMAN commands take a number of parameters and must end with a semicolon.

When you enter a line of text that is not a complete command, RMAN prompts for continuation input with a line number.

Using Command Files with RMAN

For repetitive tasks, you can create a text file containing RMAN commands, and start the RMAN client with the @ argument, followed by a filename. For example, create a text file cmdfile1 in the current directory contained one line of text as shown here:

BACKUP DATABASE PLUS ARCHIVELOG;

You can run this command file from the command line as shown in this example, and the command contained in it is executed:

$ rman TARGET / @cmdfile1

After the command completes, RMAN exits.

You can also use the @ command at the RMAN command prompt to execute the contents of a command file during an RMAN session. RMAN reads the file and executes the commands in it. For example:

RMAN> @cmdfile1