RMAN Backup Optimization Reduce Backup Size and Time

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In this article, we will discuss an important parameter in Oracle Recovery Manager (RMAN) called backup population. By optimizing the backup process, RMAN ensures that only the necessary data is backed up, reducing the size of the backup and saving valuable time. We will explore this parameter in detail, explain its function, and demonstrate how to enable and utilize it effectively.

Understanding the Backup Population Parameter

When you create a new database, the backup population parameter in RMAN is disabled by default. Its primary function is to validate if a backup of the same data set already exists before initiating a new backup. By checking for the presence of an identical backup, RMAN can optimize the backup process by only backing up the parts that have been modified or are missing in the previous backup.

This optimization technique is particularly useful in minimizing backup size and conserving writing time. It ensures that unnecessary duplication is avoided, leading to more efficient storage utilization and faster backup operations.

Enabling and Demonstrating Backup Optimization

To illustrate the benefits of backup optimization, we will walk through an example of disabling and enabling the backup population parameter in RMAN. By doing so, we can showcase the significant impact it has on the backup process.

  1. Showing the Current Parameter Value:
  2. To check the current value of the backup population parameter, execute the following command in RMAN: show configure backup_optimization;
  3. The output will display the current status of the parameter.

  4. Disabling Backup Population:

  5. To disable the parameter, execute the command: configure backup_optimization off;
  6. This ensures that the backup process will not consider previous backups.

  7. Performing a Backup:

  8. Create a backup of the desired data by executing the backup command in RMAN.
  9. After the backup is completed, check the size of the backup files using the command: show bs_i;
  10. Note the size of the backup for future comparison.

  11. Enabling Backup Population:

  12. Enable the backup population parameter by executing the command: configure backup_optimization on;
  13. This allows RMAN to utilize previous backups and optimize the current backup process.

  14. Performing a Second Backup:

  15. Create a backup of the same data that was backed up previously.
  16. During the backup process, RMAN will analyze the existing backups and only back up the necessary parts.
  17. Check the size of the backup files using the command: show bs_i;
  18. Compare the size with the previous backup to observe the reduction in size due to backup optimization.

Benefits of Backup Optimization

The implementation of backup optimization in RMAN offers several advantages for database administrators:

  1. Reduced Backup Size:
  2. By omitting the duplication of unchanged data, backups become much smaller, optimizing storage utilization.
  3. This is particularly advantageous when dealing with large databases or limited storage capacities.

  4. Faster Backup Operations:

  5. Backup optimization significantly speeds up the backup process by eliminating the need to back up unchanged data.
  6. This results in shorter backup windows and allows the DBA to allocate more time for other critical tasks.

  7. Efficient Resource Utilization:

  8. By not duplicating unnecessary data, backup optimization ensures efficient utilization of disk space, reducing storage costs.
  9. It also minimizes network bandwidth consumption and CPU usage by excluding unchanged data from the backup process.

  10. Simplified Data Recovery:

  11. With backup optimization, the recovery process becomes more streamlined and efficient.
  12. By eliminating unnecessary backups, database administrators can focus on restoring and recovering only the essential data, minimizing downtime.


In conclusion, utilizing the backup population parameter in RMAN plays a crucial role in optimizing backup processes. By ensuring that only the necessary data is backed up, both the size and the time required for backups can be significantly reduced. This optimization technique is valuable for maintaining efficient storage utilization, accelerating backup operations, and simplifying the data recovery process.

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