Oracle 11g new feature-RMAN

In addition to the simple backup and recovery functions, RMAN has been given more and more responsibilities, such as creating Standby databases, such as cross-platform transfer of table space conversion. Oracle 11G's RMAN does not have many sudden updates.

1. Customize the archivelog deletion policy

We know that before 11 GB, only the deletion policy of backupset can be defined, such as how long the backup is retained or how many valid backups are retained, however, to delete an archive log, you only need to define in the delete command the time at which all the backups have been deleted or the time point at which the archive logs are deleted. In 11g, we can use the configure command to define the deletion policy for archiving logs. For example, we have added the following syntax, only archived logs backed up twice on the tape will be deleted by the delete command.

Configure archivelog deletion policy to backed up 2 times to device type sbt;

Of course, simply adding the syntax can only be called a boring new function. Besides the configure syntax, the application ON

The STANDBY keyword defines that only archived logs that have been applied to all standby sites will be deleted, or all archived logs that have been successfully transferred to the standby site will be deleted. In the past, DBAs had to write their own scripts to query relevant information from the data dictionary and then delete the data using the script.

2. Copy the database directly through the network

If you want to use the duplicate command to copy a database before 11 GB, you need the source database and a valid backup on the target machine. The target database is required, this is greatly simplified in 11g. With the from active database keyword, we only need one source DATABASE to simply copy the same DATABASE on another machine over the network. Oracle uses a series of Memory scripts to recover the Memory and open the target database.

In addition, the duplicate database did not automatically copy the spfile before 11 GB. Now, we can use the following statement to allow Oracle to automatically generate a spfile During the replication process, the initialization parameters can be defined.

DUPLICATE TARGET DATABASE TO aux_db FROM ACTIVE DATABASE SPFILE PARAMETER_VALUE_CONVERT '/u01', '/u02' SET SGA_MAX_SIZE = '200M' SET SGA_TARGET = '125M' SET LOG_FILE_NAME_CONVERT = '/u01','/u02' DB_FILE_NAME_CONVERT '/u01','/u02';

To use duplicate to copy a database in 11g, you only need the target database (AUXILIARY instance ):

A. Use the simplest pfile to start the instance to the nomount state. This pfile only needs to contain the DB_NAME and REMOTE_LOGIN_PASSWORFILE parameters.

B. the password file must be created in advance, and the SYS password must be the same as that in the source database, which can be easily completed through orapwd.

C. The directory structure must be created in advance and have the correct permissions

3. Parallel backup of large files

Currently, a single data file in the Oracle database can be up to 128 TB, while in earlier versions, the minimum backup unit of RMAN is datafile. For such ultra-large data files that may appear in the future, RMAN backup is almost impossible. In 11g, using the section size keyword in the backup command, we can specify a section for the data file. Each section is processed as an independent unit, A maximum of 256 sections can be specified for each data file.

The advantage of Section is that you can back up multiple sections in parallel to increase the backup speed. You can back up multiple sections of a large file at multiple times, and reduce the time to zero, making it more operational.

4. RMAN Catalog Management Enhancement

The import catalog command allows us to dump information in a catalog library to another catalog library, which previously requires manual operations.

The concept of Virtual Recovery Catalogs is introduced, which is an instance application of VPD. For a centralized management Catalogs that sets Virtual catalog for multiple users, each user can only manage their own data, further improving security.