In fact, configuring RMAN options greatly assists the database administrator in their work, especially if they have a clear strategy in place for their operations. Therefore, the database administrator configures RMAN based on this pre-prepared strategy. It is also worth noting that when using RMAN without its configuration, it operates in this case on the default setting.

Of course, RMAN can be configured, but the database administrator can also choose to ignore this configuration by performing their tasks manually by writing what they want in the RMAN editor, even if it differs entirely from the configuration settings. Thus, it can be said that the process of configuring RMAN is important for the database administrator, and they can choose to ignore this configuration whenever they want to perform their tasks manually.

The database administrator can configure RMAN to specify the type of backup (Backup Set or Copy) and also determine the type of device (Tape or Disk Device), as well as the retention period for the backups and other options that we will discuss in detail.

SHOW ALL;

ALL SHOW:

This command displays the RMAN Configuration options, and you may notice that there is sometimes the word Default at the end of the line, indicating that this is the default value (Default Setting).

Retention Policy Configuration:

This is to specify the retention period for backups before these backups become obsolete (Obsolete). These backups can later be deleted using the Delete Obsolete command.

It should be noted that there are two types for configuring the retention period:

1. Specify the retention period in days.

CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 3 DAYS;

The retention period has been set for three days. You can view the new retention configuration using the command:

SHOW RETENTION POLICY;

You can revert to the original value using the command:

CONFIGURE RETENTION POLICY CLEAR;

2- Specifying the retention period by the number of copies: The default value for this option is 1 REDUNDANCY, meaning RMAN attempts to retain one backup copy for all Data Files and all Archive Log Files as well as the Control File, regardless of whether the backup is of the (Backup or Copy Image) type.

CONFIGURE RETENTION POLICY TO REDUNDANCY 3;

Default Device Type Configuration:

This is to specify whether the backup files will be directed to disk or to a tape device. By default, backup files will be directed to disk.

CONFIGURE DEFAULT DEVICE TYPE TO SBT_TAPE;

Now the backup files will be directed to the (Tape Library) unless ignored by manually directing the backups through the RMAN prompt.

Backup files can also be directed to disk using the command.

CONFIGURE DEFAULT DEVICE TYPE TO DISK;

Device Type Configuration:

SHOW DEVICE TYPE;

In the default mode, when performing a backup and sending it to disk, one channel will be used to send the backup.

The backup will be created as a Backup Set rather than an Image Copy. Of course, the Device Type can be configured when sending the backup to the Tape Library.

Let’s assume you want to use two channels operating in parallel to transfer backup files when sending the backup to the Tape Library, and the backup type will be Backup Set.

Note that backups of type Image Copy cannot be sent to the Tape Library.

CONFIGURE DEVICE TYPE SBT_TAPE PARALLELISM 2 BACKUP TYPE TO BACKUPSET;

Channel Allocation:

As previously mentioned, it is essential to allocate channels to perform backup and recovery operations, whether done manually using the Allocate Channel command or by configuring the channel via the Configure Channel command. The maximum number of channels that can operate in parallel depends on the operating system.

There are several options for controlling the channels:

1. DURATION: To control the time taken to execute tasks via the channel, which is specified in hours and minutes. This option can affect the speed of operations using one of the following options:

• MINIMIZE TIME: Specified to ensure that operations are executed as quickly as possible, but the operation may complete before the specified time. This usually occurs when sending backups to Tape, as it is preferable to send data to tapes as quickly as possible.
• MINIMIZE LOAD: Specified to monitor the speed of backup operations and reduce it if it is determined that it will finish before the allotted time. This variable is usually set when sending backup files to disk to reduce the impact on users due to increased load on the disk.

1. FORMAT: To specify the path and name of backup files.
2. MAXOPENFILES: To specify the number of files that the channel can open at one time, with a default of 8.
3. MAXPIECESIZE: To specify the size of the backup file created by the channel.

CONFIGURE CHANNEL DEVICE TYPE DISK MAXOPENFILES ٦ MAXPIECESIZE 2G;

Configuration of AUTOBACKUP CONTROLFILE:

This means whether we want to automatically create a backup of the Control File and SPFILE each time we perform a backup operation or not. By default, this variable is set to OFF, meaning that the Control File is not backed up automatically during backup operations.

This variable can be configured to take the value ON, allowing an automatic backup of the CONTROL FILE whenever any backup operation is conducted. This is particularly important when we are not using a Recovery Catalog, as backup information is stored in the Control File, making the preservation of this information more critical.

CONFIGURE CONTROLFILE AUTOBACKUP ON;

Configuration of Control File AutoBackup Format:

To specify the path and name of the automatic backup files for CONTROL FILES.

CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO 'C:\%F';

EXCLUDE Configuration:

Sometimes, you may have a Tablespace in Read Only mode, Offline mode, or it could even be Online but not active, meaning it contains static data.

In these cases and others, you may not need to perform a backup for this Tablespace during the full database backup, which reduces both the time and size of the backup files.

A list of the Tablespaces to be excluded during the backup process can be specified.

CONFIGURE EXCLUDE FOR TABLESPACE USERS;

BACKUP OPTIMIZATION Configuration:

This option defaults to OFF and can be configured to ON to ignore all objects that have not changed since the last backup.

CONFIGURE BACKUP OPTIMIZATION ON;

Configuration of DATAFILE BACKUP COPIES & ARCHIVELOG BACKUP COPIES:

To determine the number of copies created when performing a backup of Data Files or Archive Log Files.

CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1;
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1;

A single backup copy is specified for both Data Files and Archive Log Files

Setting the MAXSETSIZE: This is the maximum size for backups of the type Backup Set, and by default, this option takes the value Unlimited.

CONFIGURE MAXSETSIZE TO 4G;