RMAN backup and recovery: Protecting your Oracle databases

Data backup and recovery processes are essential for operational efficiency and peace of mind. Think of all the valuable content stored in your organization's database. From essential internal documentation to sensitive client data and beyond, data resources today are too valuable to take for granted.

If your company uses Oracle database technology, the system you'll need to deal with is the Oracle Recovery Manager (RMAN) environment. Since Oracle database deployments can vary so widely based on businesses' needs, there are a host of configurable features within RMAN. Using this disaster recovery technology correctly may be the difference between a smooth backup experience and a major incident.

Why are database backup processes so important?

Getting a database environment back online following an incidence of downtime depends on your database backup and disaster recovery strategy. A natural disaster or a more concentrated incident such as a flooded data center or network outage could put your Oracle database environment at risk, at which point it's up to your team to restore functionality — fast.

To keep your company effective and productive, you need to have access to your database at all times. Every minute the Oracle data resources are offline could be leading to wasted time and the lost value that comes along.

Your data backup strategy should involve archiving and backups that enable you to quickly switch over and stay running, even if a destructive emergency strikes an office or data center. In the case of Oracle database deployments, this means becoming a power user of the Oracle RMAN utility. Having an Oracle database backup ready to go will suddenly become priority No. 1 if your organization suffers a disaster.

How does Oracle RMAN backup work?

Oracle documentation notes that by using the RMAN client, users can simplify their Oracle database backup experiences. This set of utilities allows you to perform common backup and recovery tasks with less need for manual entry of commands.

At the most basic level of implementation, you will just have the RMAN client and the database you choose to connect it to. Additional components that users can implement include:

• A media manager application (for use with tape libraries and other media devices).
• A dedicated area of a disk set aside for fast recovery files.
• A recovery catalog, preserving RMAN metadata to guard against the loss of the RMAN control file.

While the RMAN client supports the use of more advanced Oracle data recovery strategies, reflecting companies' different needs and data retention policies, the basic options are relatively simple.

The basic "BACKUP" command can be modified to tell the system where to create the database and what it should be labeled. If the company has specified a fast recovery pathway, the RMAN backups will be placed on the dedicated disk and given unique names. By default, the names reflect the date and time of the backup.

There are a series of commands database administrators can use to make sure their database backup operations are running correctly. These include "NEED BACKUP," which tells users which files have not received recent-enough RMAN backups in line with the organization's policies. The "UNRECOVERABLE" backup command identifies files that have had unrecoverable actions performed since the previous backup.

"OBSOLETE," another helpful backup command for an Oracle DBA, helps users figure out when database recovery files have been superseded and are no longer needed under the rules of their data retention strategies. By combining this with the "DELETE" command to make "DELETE OBSOLETE," DBAs gain a one-stop way to wipe out copies and files that are no longer necessary.

RMAN incremental backup operations

The RMAN client includes ways to make database backups simpler to perform. The main way to make database recovery operations less of a heavy lift for companies' systems is to perform incremental backups, only updating the backed-up versions of files that have changed rather than copying the whole database.

The incremental backup process, as described in Oracle documentation, begins with a level 0 incremental backup. In essence, this is a full backup of the target database, including every block of data. The system considers it the foundation of the incremental strategy, however, rather than treating it as a full backup. 

From there, it's time to perform level 1 incremental backups. There are two forms of level 1 backups. Cumulative backups are based on all blocks changed since the last level 0 backup was made. A differential backup reflects only changes made since the most recent incremental backup whether it was level 1 or level 0.

Oracle recommends cumulative backups when focusing on recovery time. This is because they are more wide-ranging, and therefore when recovering the database, there will be fewer individual incremental backups to deal with. Differential backup operations, on the other hand, provide a way to save disk space resources.

How do you implement Oracle RMAN backup effectively?

When working with an expansive, feature-laden system such as an Oracle database implementation, the sheer number of options can cause some useful capabilities to go overlooked. Whether your IT team is working alone or in collaboration with expert consultants, you can improve your database's performance by considering all possible features and adopting best practices.

The exact mix of capabilities that will work for your business will depend on how you use your database and what type of information you store. Some promising options include:

Using a recovery catalog

A recovery catalog represents a way to expand RMAN backup capabilities beyond what would be possible with a standard control file. The catalog can store additional metadata and allows DBAs to keep metadata for multiple databases in a single file.

Enabling automatic backups of control files and parameters

It's possible to enable RMAN to create a new backup for database control files and server parameter files when certain types of changes occur. These automatically updated files allow Oracle backup recovery to occur even if original configuration files are lost, and it's helpful to automatically back up control files for both primary and standby databases.

Turning on block change tracking for incremental backup

Since incremental backup processes are based on backing up fewer files to save resources, options that allow even further streamlining are useful. As of recent Oracle releases, it's possible to enable block change tracking for both primary and standby databases. This option detects what blocks of data have changed without scanning the whole database, enabling more efficient incremental backup.

Recovering time-based states with flashback and point-in-time recovery

Oracle's Flashback Technology and point-in-time recovery functionality are designed to return databases to former states. These features are quicker and more efficient to use, allowing an Oracle DBA to view several states and not limit database availability as much as they would if performing a full data restoration. 

Performing block media recovery on individual damaged blocks

Block media recovery is designed to be a highly efficient form of recovery, based on recovering only corrupt blocks. A data file can stay online during recovery with block media recovery enabled — corrupt blocks normally force each data file to go offline during the recovery process. Block media recovery also enables quick mean times to recover by only repairing blocks that need attention.

Going beyond the basics with RMAN backup can create an optimized experience that will keep your Oracle databases operating reliably, with a minimum amount of resources expended. The tools exist within the software to enable this level of performance, provided you have a team of internal or external experts to implement them.

What other Oracle database services should your organization pursue?

Backup and recovery via RMAN are just a few of the advanced capabilities your IT team can tap into when working with Oracle databases. Keeping up with the latest releases of Oracle Database products means both tuning for better performance and taking advantage of newly introduced features. In recent years, organizations have also been increasingly moving their Oracle instances to the cloud — you can become part of this mass migration.

Sometimes, Oracle optimization can be as simple as entering one command to change a parameter or turn a feature off. In other cases, it's worth rethinking your implementation on a more fundamental level to drive better performance. In any case, focusing on database performance is worthwhile due to the frequency of database use. Even seemingly minor upgrades can have a big impact on everyday workflows.

Optimizing an Oracle implementation, whether around backup and recovery or any other features that match your business's needs, is worth exploring with the help of third-party experts and consultants. Specialists with a focus on database technology may bring valuable perspectives on the ideal moves for your configuration.

Working with an expert database partner on backup and more

Dealing with the many variables around RMAN backup to create the ideal Oracle database backup strategy is easier when your company has a team of experts on its side. Working with Solvaria, whether for an Oracle backup strategy implementation or a more extended managed services engagement, is a way to ensure your Oracle backups are effective, without over-leveraging internal resources.

Not every business will have the amount of IT services personnel and budget to create an effective RMAN backup strategy. However, database backup and recovery processes are so important to the smooth operation of today's organization that you can't neglect this aspect of your IT operations.

This is where a Solvaria engagement can have a truly positive impact on your organization, increasing your engagement with advanced database operations without forcing you to add salaries to the payroll. For Oracle RMAN backup, other Oracle database management tasks and more, Solvaria experts can become trusted members of your team.

Contact Solvaria now to get started with an assessment of your current database needs and your ideal next steps.