Objetivos de las preguntas de las encuestas

RMAN consists of several components that interact during the backup and recovery process.

10.1.2 RMAN Command

The RMAN command is the administrator's interface to RMAN. It invokes a command line interface that provides an operating-system-independent scripting language for performing backup and recovery operations. RMAN can be executed either interactively, where a command prompt is displayed and additional RMAN commands entered, or in batch mode, where an RMAN script containing commands is executed.

10.1.3 Target Database

The target database is the Oracle8 database instance on which RMAN executes specified backup, restore, and recovery actions. When the RMAN command is executed, it connects to the target database. The target database is specified by using RMAN parameters.

10.1.4 Communication Channel

RMAN can perform backup and restore functions to either local disk or to external media management products such as an TSM server through the orasbt.dll library provided by TDP for Oracle for Windows. These I/O operations are performed over a communication channel that defines the device to be used for the operation. The channel is used by RMAN to send or receive backup data to and from the I/O device.

For backup and restore operations, you must allocate a channel before the operation is performed. A channel corresponds to a single device. With the TDP for Oracle for Windows, a channel is a single session to an TSM server. Multiple channels can be allocated. RMAN provides a multiplexing feature that enables parallel data streams to be sent over multiple allocated channels to maximize backup and recovery performance.

10.1.5 Recovery Catalog

The recovery catalog is the repository for information about backup objects created by RMAN. It is a Oracle8 database instance, separate from the target

6249ch09.fm Draft Document for Review May 2, 2001 8:03 pm databases, and can contain information for multiple target databases. The data stored in the recovery catalog comprises structural information about the target databases to back up and restore. The recovery catalog contains information about:

• Physical schema of a target database

You have to register the target database at the recovery catalog to define the physical schema of the target database. RMAN needs to know about any structural change of the target database and obtains this information from the target database control file.

• Database backup history

RMAN backs up databases, tablespaces, data files, control files, and archive logs to the TSM server. Details of these backup objects held on TSM is stored in the recovery catalog.

• Backup and recovery history

RMAN stores backup, restore, and recovery information to maintain a history of previously performed operations. When backup and restore operations are performed, this information enables RMAN to determine: - Database files that require backing up

- Old backup files that can be deleted - Files that are not recoverable • Stored RMAN scripts

RMAN commands can be stored in the recovery catalog as stored scripts. Scripts can be created to automate the execution of a several RMAN operations.

Oracle strongly recommends that a recovery catalog be used with RMAN. However, it is possible to execute RMAN commands without one. If you operate without a recovery catalog, RMAN uses the target database control file to store backup and structural information about the database. The following limitations apply when operating without recovery catalog: • Point-in-time recovery is not possible.

• Stored RMAN scripts cannot be used.

• Recovery cannot be performed if the control files are lost or damaged. Oracle recommends the use of multiplexed control files, with each file located on different disks to protect against media failure.

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Figure 68. RMAN and TSM system components

The operation is started by invoking the command rman and entering the

appropriate commands directly or by submitting a command file containing

the commands. 1

RMAN connects to the recovery catalog 2

and the target database3.

Before any backup or restore operations can be performed, RMAN allocates a

channel to TSM, using the SBT API 4.

RMAN then creates a server process on the target database instance 5 that

performs the operation.

For restore operations RMAN queries the recovery catalog to determine which files to restore from TSM. For a backup operation RMAN backs up the

6249ch09.fm Draft Document for Review May 2, 2001 8:03 pm objects specified in the command to TSM. In both cases the data is

transferred on the previously defined channel.

10.1.6 Create the RMAN catalog

The procedure we used to create the recovery catalog is described in the manual Oracle8i Recovery Manager User’s Guide and Reference

Below is a sample print screen of the creation of the user rman Figure 69 and of the create catalog command Figure 70.

Figure 69. create user rman

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10.1.7 Registering the target database

Having created a recovery catalog, you must register the target databases to it. Use RMAN commands. Registration must be done before any other RMAN functions can be performed on the target databases.

You register each of the target database instances that will use the recovery catalog. As the Oracle user run the rman command to connect to the target and recovery catalog databases and then run the register database

command.

The following example shows the commands to connect to the BEACH target database as the internal user and the RIO recovery catalog database as the newly created rman user, followed by the target database being registered

To list the result of the register command use report schema.

C:\oracle\ora81\network\ADMIN>rman target internal/manager@beach rcvcat "rman/rman@rio

Recovery Manager: Release 8.1.7.0.0 - Production

RMAN-06005: connected to target database: BEACH (DBID=24844426) RMAN-06008: connected to recovery catalog database

RMAN> register database;

RMAN-03022: compiling command: register RMAN-03023: executing command: register

RMAN-08006: database registered in recovery catalog RMAN-03023: executing command: full resync

RMAN-08002: starting full resync of recovery catalog RMAN-08004: full resync complete

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