RMAN Backup and Recovery Interview Questions

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Introduction: –

RMAN Backup And Recovery Interview Questions| Here is useful RMAN Backup and Recovery Interview Questions/Answers for DBA.

Below are oracle rman interview questions.

Q⟹ What is RMAN?

A⟹RMAN is an Oracle Database client that performs backup, restoration,
recovery and administrative tasks in oracle Database. It greatly simplifies the dba jobs by managing the production database’s backup, restoration, and recovery.

This tool integrates with sessions running on an Oracle database to perform a range of backup and recovery activities, including maintaining an RMAN repository of historical data about backups. There is no additional installation required for this tool. It’s by default get installed with the oracle database installation. The RMAN environment consists of the utilities and databases that play a role in backing up your data.You can access RMAN through the command line or through Oracle Enterprise Manager.

Q⟹ Difference between expired backup and obsolete backup.

A⟹ In RMAN ‘expired’ means that the backup piece or backup set is not found in the backup destination. … Therefore, the backup piece is expired as well. A status of ‘obsolete’ means the backup piece is still available, but it is no longer needed.

Q⟹ What does mean by Level 0, Level 1 backups: –

A⟹ level 0 incremental backup, which copies all blocks in the data file, is used as a starting point for an incremental backup strategy. A level 0 is physically identical to a full backup. The only difference is that the level 0 backup is recorded as an incremental backup in the RMAN repository, so it can be used as the parent for a level 1 backup. A level 1 incremental backup copies only images of blocks that have changed since the previous level 0 or level 1 incremental backup.

RMAN> BACKUP INCREMENTAL LEVEL 0 DATABASE;

RMAN> BACKUP INCREMENTAL LEVEL 1 DATABASE;

RMAN Backup And Recovery Interview Questions

To qualify the Backup and Recovery interview we have to know about all RMAN configuration. Simply we can check the current configuration using show all command on rman prompt.

Q⟾ How to check RMAN configuration.

A⟹ By using command

RMAN> show all;

Q⟾ Can we take the rman backup while database in shutdown.

A⟹ No, Database should be in mount or open mode. For Open mode archivelog must be enable in oracle database.

Q⟾ Difference between backup piece and backup set.

A⟹ Backup piece is physical and backup set is logical.

Q⟾ Crosscheck command in RMAN.

A⟹ CROSSCHECK command to synchronize the physical reality of backups and copies with their logical records in the RMAN repository. If a corresponding backup is not available on the disk, then Crosscheck command marks the backup as Expired otherwise it marks it as Available.

To check status of all rman backup.

RMAN> crosscheck backup;

Q⟹ How to Reset to default Configuration?

A⟹ Below command to reset default rman configuration

SQL> connect <sys/passwd as sysdba>@target_database;

SQL> execute dbms_backup_restore.resetConfig;

Q⟹ RMAN terminology

A target database: An Oracle database to which RMAN is connected with the TARGET keyword. A target database is a database on which RMAN is performing backup and recovery operations. RMAN always maintains metadata about its operations on a database in the control file of the oracle database.

RMAN>rman target sys;

A recovery Catalog: A separate database schema used to record RMAN activity against one or more target databases. A recovery catalog preserves RMAN repository metadata if the control file is lost, making it much easier to restore and recover following the loss of the control file. The database may overwrite older records in the control file, but RMAN maintains records forever in the catalog unless deleted by the user.

Backup sets: RMAN can store backup data in a logical structure called a backup set, which is the smallest unit of an RMAN backup. One backup set contains one or more datafiles a section of datafile or archivelogs.

Backup Piece: A backup set contains one or more binary files in an RMAN-specific format. This file is known as a backup piece. Each backup piece is a single output file. The size of a backup piece can be restricted; if the size is not restricted, the backup set will comprise one backup piece. Backup piece size should be restricted to no larger than the maximum file size that your filesystem will support.

Image copies: An image copy is a copy of a single file (datafile, archivelog, or controlfile). It is very similar to an O/S copy of the file. It is not a backupset or a backup piece. No compression is performed.

Snapshot Control file: When RMAN needs to resynchronize from a read-consistent version of the control file, it creates a temporary snapshot control file. The default name for the snapshot control file is port specific.

Database Incarnation: Whenever you perform incomplete recovery or perform recovery using a backup control file, you must reset the online redo logs when you open the database. The new version of the reset database is called a new incarnation. The reset database command directs RMAN to create a new database incarnation record in the recovery catalog. This new incarnation record indicates the current incarnation.

Q⟹ What are the database file’s that RMAN can backup?

A⟹RMAN can backup objects such as Controlfile , Datafiles , Archive logs , standby database controfile, Spfile.

What is RMAN consistent backup and inconsistent backup?

A⟹ A consistent backup occurs when the database is in a consistent state (not in open mode). That means backup of the database taken after a shutdown immediate, shutdown normal or shutdown transnational. If the database is shutdown with abort option, then it’s not a consistent backup.

A backup when the database is up and running is called an inconsistent backup. When a database is restored from an inconsistent backup, Oracle must perform media recovery before the database can be opened, applying any pending changes from the redo logs. You cannot take inconsistent backup when the database is in No Archivelog mode.

What is Oracle Secure backup?

A⟹ Oracle Secure Backup is a media manager provided by oracle that provides reliable and secure data protection through file system backup to tape. All major tape drives and tape libraries in SAN, Gigabit Ethernet, and SCSI environments are supported.

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