Oracle RMAN Tutorial

In this document, we will learn what is RMAN and how to take Oracle Database Backup – “Oracle RMAN tutorial”.

What is Oracle RMAN used for?

RMAN, or Recovery Manager, is a tool created by Oracle to handle backup and recovery tasks within Oracle databases. It simplifies processes such as data file backups, control file backups, and managing archived redo logs.

RMAN offers features like incremental backups, detecting block-level corruption during backups, parallel execution for quicker backup and restore operations, and seamless integration with Oracle Enterprise Manager for monitoring and reporting.

It plays a vital role in Oracle’s backup and recovery strategy, ensuring the reliability and efficiency of database backups while ensuring data availability.

How do I run a full backup in RMAN? – Oracle RMAN tutorial

To initiate a full backup using RMAN, you first need to connect to the target database using the RMAN command-line interface or through a script. Once connected, you can execute the following steps:

1. Start RMAN

Open a terminal or command prompt and type “rman” to launch the RMAN utility.

connect with rman


connect with rman target

2. Connect to the target database

Within the RMAN prompt, connect to the Oracle database you want to back up by providing the necessary credentials.

connect target

3. Begin backup

Once connected, issue the command “backup database” to perform a full backup of the entire database, including data files, control files, and archived redo logs.

RMAN> backup database;

4. Monitor progress

RMAN will display progress messages as it performs the backup. You can monitor the backup progress and any errors that may occur during the process.

5. Complete backup

Once the backup is finished successfully, RMAN will provide a completion message, indicating that the full backup process is complete.

rman backup

6. Exit RMAN

After the backup is done, you can exit the RMAN utility by typing “exit” or pressing Ctrl+C, depending on your operating system.

RMAN> exit

By following these steps, you can run a full backup of your Oracle database using the RMAN utility, ensuring that your data is securely backed up for recovery purposes. “Oracle RMAN tutorial”

How many types of RMAN backup are there?

In RMAN, there are several types of backups you can perform:

1. Full Backup

This type of backup copies the entire database, including all data files, control files, and archived redo logs.

2. Incremental Backup

Incremental backups only copy the data blocks that have changed since the last backup, reducing backup time and storage requirements compared to full backups.

3. Differential Backup

Differential backups copy all blocks that have changed since the last full backup, regardless of whether they were backed up in previous differential backups.

4. Cumulative Backup

Cumulative backups copy all blocks that have changed since the last full backup, as well as any blocks changed since the last cumulative or differential backup. This ensures that each cumulative backup contains all changes made since the last full backup.

These backup types provide flexibility and efficiency in managing the backup and recovery process in Oracle databases using RMAN. “Oracle RMAN tutorial”

What is level 0 and level 1 backup?

Level 0 and Level 1 backups are specific types of incremental backups used in RMAN:

1. Level 0 Backup

This is a baseline backup that copies all data files in the database. It serves as a starting point for subsequent incremental backups. Level 0 backups are typically performed less frequently, such as weekly or monthly, and provide a complete snapshot of the database at that point in time.

2. Level 1 Backup

Level 1 backups are incremental backups that copy only the blocks that have changed since the last backup, whether it’s a Level 0 or Level 1 backup. Level 1 backups are performed more frequently, such as daily or hourly, and they help reduce backup time and storage requirements compared to full backups.

By combining Level 0 and Level 1 backups, you can create a comprehensive backup strategy that balances between capturing complete snapshots of the database and efficiently capturing changes made since the last backup. “Oracle RMAN tutorial”

How do I calculate RMAN backup size?

To calculate the size of an RMAN backup, you need to consider several factors:

  1. Data Files Size: Determine the total size of the data files in your Oracle database. This includes all data files containing actual database information.
Check the datafile size: select sum(bytes)/1024/1024 from v$datafile;

And free space in datafile: select sum(bytes)/1024/1024 from dba_free_space;

Then subtract the free space from the datafile size.
  1. Control Files Size: Include the size of the control files, which are essential for database operations and recovery.
  2. Archived Redo Logs Size: Consider the size of archived redo logs, which record all changes made to the database and are crucial for recovery.
  3. Backup Set Size: Estimate the size of the backup set created by RMAN. This includes the actual backup data, as well as any overhead from RMAN’s backup metadata and compression algorithms.
  4. Incremental Backup Size (if applicable): If you’re performing incremental backups, calculate the size of the incremental changes since the last backup.

By summing up these factors, you can estimate the overall size of your RMAN backup. Keep in mind that RMAN may also offer features like compression, which can further reduce the backup size compared to the raw database size. “Oracle RMAN tutorial

Convert Physical Standby To Snapshot Standby

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