How to Identify RMAN Configuration in Oracle Database

 

RMAN (Recovery Manager) is a powerful tool provided by Oracle to manage backup, restore, and recovery operations. To ensure that your Oracle database is properly backed up and recoverable, it's important to understand the RMAN configuration settings.

Identifying your RMAN configuration allows you to verify and modify the backup strategies, retention policies, and other parameters essential for maintaining a healthy and recoverable database. In this blog post, we'll walk through how to identify the RMAN configuration settings in Oracle.

1. Connecting to RMAN

Before you can check the RMAN configuration, you need to connect to RMAN. You can do this from the Oracle command line interface or SQL*Plus.

1. Log in as the Oracle user on your database server.
2. Open a terminal or command prompt.
3. Run the following command to connect to RMAN:

rman target /

This command connects RMAN to the target database as a user with appropriate privileges (typically the Oracle DBA user).

Alternatively, if you need to connect to a remote database:

rman target sys/password@db_name

Once you're connected to RMAN, you can start checking the configuration.

2. Identifying RMAN Configuration

Once you're connected to RMAN, you can view the configuration settings using the SHOW CONFIGURATION command. This will display the current RMAN configuration for your Oracle database, including backup parameters, retention policies, and other settings.

Run the following command:

SHOW CONFIGURATION;

This will return a list of current RMAN configuration settings, such as:

• Backup retention policies (e.g., days for keeping backups)
• Maximum backup sets for each backup
• Compression settings
• Backup destination directories
• Parallelism settings

Here’s an example of what the output might look like:

RMAN configuration parameters for database with db_unique_name ORCL are:
  CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
  CONFIGURE BACKUP OPTIMIZATION OFF;
  CONFIGURE DEFAULT DEVICE TYPE TO DISK;
  CONFIGURE CONTROLFILE AUTOBACKUP ON;
  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/u01/app/oracle/flash_recovery_area/%F';
  CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;
  CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1;
  CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1;
  CONFIGURE MAXSETSIZE TO UNLIMITED;
  CONFIGURE COMPRESSION ALGORITHM 'BZIP2';

3. Key RMAN Configuration Parameters to Check

Here are some of the most important RMAN configuration parameters you might want to review:

1. Retention Policy

   • Defines how long backups are kept before being automatically deleted. You can configure it by either redundancy (number of backups) or by time.
   • Example:

     
     CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
     

2. Backup Optimization

   • Determines whether RMAN will skip backups of unchanged data files. This can save storage space.
   • Example:

     
     CONFIGURE BACKUP OPTIMIZATION ON;
     

3. Backup Type

   • Defines whether to use BACKUPSET (recommended) or IMAGE COPY for backups.
   • Example:

     
     CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO BACKUPSET;
     

4. Parallelism

   • Controls the number of parallel backup operations that can run simultaneously, which can improve performance, especially on large databases.
   • Example:

     
     CONFIGURE DEVICE TYPE DISK PARALLELISM 4;
     

5. Compression

   • Specifies whether RMAN should use compression for backups, which can help save storage space. Common algorithms include ZLIB and BZIP2.
   • Example:

     
     CONFIGURE COMPRESSION ALGORITHM 'BZIP2';
     

6. Control File Autobackup

   • Ensures that RMAN automatically backs up the control file after each backup, which is important for recovery.
   • Example:

     
     CONFIGURE CONTROLFILE AUTOBACKUP ON;
     

7. Flash Recovery Area

   • Defines the location where backups and archived logs are stored, helping with recovery.
   • Example:

     
     CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/u01/app/oracle/flash_recovery_area/%F';
     

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4. Changing RMAN Configuration

If you need to modify any of these RMAN configuration settings, you can use the CONFIGURE command followed by the desired option. For example, to change the backup retention policy:

CONFIGURE RETENTION POLICY TO REDUNDANCY 3;

This would ensure that RMAN keeps the last 3 backups for each datafile.

To turn off backup optimization:

CONFIGURE BACKUP OPTIMIZATION OFF;

5. Viewing and Verifying Specific Parameters

If you need to verify a specific parameter, you can check it by running the SHOW command for that parameter:

SHOW RETENTION POLICY;
SHOW BACKUP OPTIMIZATION;
SHOW COMPRESSION ALGORITHM;

This will give you a quick view of individual configuration parameters.

6. Using RMAN with Oracle Enterprise Manager (OEM)

If you have Oracle Enterprise Manager (OEM) installed, you can also view and manage RMAN configuration settings from the OEM interface, which provides a user-friendly graphical interface for managing backup strategies.

Identifying the RMAN configuration in Oracle is an essential step in ensuring that your backup and recovery strategy is correctly set up. By using the SHOW CONFIGURATION command, you can easily review your RMAN settings and verify that everything is configured to meet your business needs.

Remember, it's crucial to keep these configurations optimized according to your database's size, the business requirements, and the recovery objectives. Regularly reviewing and adjusting the RMAN configuration ensures that your backup and recovery processes run smoothly and that your Oracle database is fully protected.