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NetVault Plug-in for Oracle 7.1 - User Guide

Introducing Dell™ NetVault™ Backup Plug‑in for Oracle® Defining a backup strategy Installing and removing the plug-in Configuring the plug-in Backing up data Using the Oracle Flashback Database Restoring data
Restoring and recovering data – an overview Performing User Managed restores Using advanced User Managed restore procedures Performing RMAN restores Using RMAN types of recovery in a non-RAC environment Using advanced procedures with RMAN restores
Maintaining the Recovery Catalog Using the RMAN CLI Using the Plug-in with Oracle RAC Using the Plug-inin a failover cluster environment Using the plug-in with Oracle Data Guard Troubleshooting Glossary About Dell

Developing a Recovery Catalog backup strategy

The Recovery Catalog database is similar to any other database, and must be a key part of your backup-and-recovery strategy.
Oracle recommends that you back up the Recovery Catalog with the same frequency that you back up the target database. For example, if you make a weekly whole-database backup of the target database, back up the Recovery Catalog immediately after all target database backups to protect the record of the whole-database backup. This backup can also help you in a disaster recovery scenario. Even if you have to restore the Recovery Catalog database using a Control File Autobackup, you can then use the full record of backups in your restored Recovery Catalog database to restore the target database without using a Control File Autobackup for the target database.
Oracle recommends the following guidelines for an RMAN backup strategy for the Recovery Catalog database:
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Run the Recovery Catalog database in ARCHIVELOG mode so that PIT Recovery is possible.
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Back up the database onto two separate media (for example, disk and tape).
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Include Archived Log files in your backups.
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Do not use another Recovery Catalog as the repository for the backups.
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Configure the Control File Autobackup feature to ON.

Examples of backup sequences

Following are a few examples of backup sequences that can be implemented to meet the data protection requirements of your Oracle Database Server.
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Full Backups only – When business requirements guarantee data protection up to the previous day, performing full backups on a daily basis should be sufficient. DBAs are only required to recover the database up to the point of the last full backup.
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Full Backup and Archived Log Backups – When business requirements mandate PIT data protection but recovery time is not important, Full Backups coupled with Archived Log backups should provide the necessary protection.
For example, Full Backups are performed every Sunday night at 11:00 p.m., while Archived Log backups are performed Monday through Saturday at 11:00 p.m.
This strategy will require RMAN to restore and apply each Archived Log backup between the last Full Backup and the point-of-failure in succession. This can lead to longer recovery as the week progresses. To speed up restores, you can include Incremental backups, which will reduce the number of Archived Log backups that must be restored.
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Incremental Level 0 and Differential Incremental Level 1 and Archived Log Backups – When business requirements mandate PIT data protection and backups have to be as fast as possible, Incremental Level 0 and Differential Incremental Backup and Archived Redo Log backups is an ideal strategy.
For example, Incremental Level 0 backups are performed every Sunday night at 11:00 p.m., while Differential Incremental Level 1 backups are performed Monday through Saturday at 11:00 p.m., and Archived Log backups are performed every 5 to 6 hours. Each Differential Incremental Level 1 backup will include all the changes since the last Level 0 or Level 1 backup, and the Archived Log backups will include the transaction logs since the last Differential Incremental Level 1 backup.
This strategy can lead to longer recovery because RMAN must restore the Incremental Level 0 backup, each Differential Incremental Level 1 backup since the Incremental Level 0 backup, and the Archived Log backups between the last Differential Incremental backup and the point-of-failure.
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Incremental Level 0 and Cumulative Incremental Level 1 and Archived Log Backups – When business requirements mandate PIT data protection and recovery time should be as fast as possible, Incremental Level 0 and Cumulative Incremental Level 1 and Archived Log backups are the best combination.
For example, Incremental Level 0 backups are performed every Sunday night at 11:00 p.m., while Cumulative Incremental Level 1 backups are performed Monday through Saturday at 11:00 p.m. and Archived Log backups are performed every 5 to 6 hours. Each Cumulative Incremental Level 1 backup will include all the changes since the last Incremental Level 0 backup, and the Archived Log backups will include the Redo Logs since the last Cumulative Incremental Level 1 backup.
This strategy leads to quick recovery because RMAN only has to restore the Incremental Level 0 backup, the last Cumulative backup, and the Archived Log backups created between the last Cumulative backup and the point-of-failure.

Defining a Backup Destination strategy

When FRA is enabled, Backup Destination options are enabled on the Backup Options tab. These options let you select the destination for the backup. These options let you define a media destination strategy that best meets your needs.
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Tape (Backup to NetVault Backup Media) – This is the default option. When selected, RMAN opens an “SBT_TAPE” channel and writes the backup files to the backup media that is managed by NetVault Backup and specified in the Device options section of the Target tab. NetVault Backup can manage a wide range of backup devices, including disk-based media, VTLs, and tape drives, which lets you implement a Disk-to-Disk-to-Tape backup strategy. Even though FRA has been enabled for the database, it is not used to store backup recovery files. This is ideal for users who want to maintain a dedicated FRA for permanent files such as copies of the current Control File and online redo logs or Flashback logs.
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Disk (Backup to FRA) – When selected, RMAN opens a DISK channel and only writes the backup files to the FRA. Storing the backup recovery files in the FRA provides the fastest restore possible with RMAN because RMAN can restore the files directly from the FRA without having to read files from backup media. Because the FRA is typically disk storage residing on the same local or shared storage as the datafiles, it does not provide complete protection against complete media failure, corruption, or disaster recovery. To ensure that the backup recovery files are stored in offsite storage, you can use the Both Tape and Disk or perform periodic Flash Recovery Area Backups to back up the backup recovery files stored in the FRA-to-backup media managed by NetVault Backup.
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Both Tape and Disk (Backup to FRA then Backup FRA to NetVault Backup Media) – Implementing a Tape and Disk backup strategy provides the most protection with the fastest restores. When selected, RMAN opens a DISK channel and writes the backup files to the FRA followed by a backup of the backup recovery files stored in the FRA-to-backup media managed by NetVault Backup in the same backup job. This lets you perform the fastest recovery possible from isolated media failure and data corruption while providing offsite protection for complete media failure or disaster recovery. Selecting the Both Tape and Disk option will lengthen the duration of the backup job because RMAN must perform two types of backups in the same backup job.
For those who want to store backup recovery files in the FRA for faster restores and require offsite protection for disaster recovery but do not want to lengthen the duration of the daily backup jobs, there is an additional option for performing daily backups to the FRA while performing Flash Recovery Area Backups on a different independent schedule. For example, when Full Backups are performed every Sunday at 11:00pm, they are performed to Disk. When Incremental Backups are performed Monday through Saturday at 11:00pm, they are also performed to Disk. However, a Flash Recovery Area Backup to backup media is performed on a weekly basis every Sunday at 10:00pm before the Full Backup is performed. Additionally, you have the option to perform the Flash Recovery Area Backup at any interval that meets business requirements.
 
 
*NOTE: The Flash Recovery Area feature is not available in Oracle 9i; using the Both Tape and Disk option with Oracle 9i might result in unexpected Oracle errors.

Oracle Flashback technology

Versions 10g and later of Oracle Database provide a group of features known as Oracle Flashback Technology. Flashback Technology features include the Oracle Flashback Database, Oracle Flashback Table, and Oracle Flashback Drop. Flashback Technology supports viewing past states of data and winding data back and forth in time without requiring you to restore the database from backup. Depending on the changes to your database, Flashback Technology features can often reverse the unwanted changes more quickly and with less impact on database availability than media recovery.
According to Oracle Corporation, the Oracle Flashback Database lets you rewind an Oracle database to a previous time to correct problems caused by logical data corruptions or user errors. Plug‑in for Oracle provides support for Flashback Database via the NetVault Backup WebUI, which enables point-and-click Flashback Database options as an alternative to media recovery.
If an FRA is configured and you have enabled the Flashback Database functionality, you can use the FLASHBACK DATABASE command to return the database to a prior time. Flashback Database is not true media recovery because it does not involve restoring physical datafiles. Flashback Database is preferable to using the RESTORE and RECOVER commands in some cases because it is faster and easier and does not require restoring the whole database.
The time it takes to rewind a database with FLASHBACK DATABASE is proportional to how far back in time you need to go and the amount of database activity after the target time. The time it would take to restore and recover the whole database could be much longer. The before images in the flashback logs are only used to restore the database to a point in the past, and forward recovery is used to bring the database to a consistent state at some time in the past. Oracle Database returns datafiles to the previous point-in-time, but not auxiliary files, such as initialization parameter files.
Dell recommends that you enable Flashback Database for Oracle 10g and later databases so that the administrator can flashback the database to correct problems caused by logical data corruptions or user errors. For more information on Flashback Database, refer to Oracle Flashback Technology in Oracle Database Concepts and to Configuring Oracle Flashback Database and Restore Points in the Oracle Database Backup and Recovery User’s Guide.
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