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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

Reviewing the available backup methods

Plug‑in for Oracle offers two backup methods: User Managed and RMAN. The plug-in supports implementing a pure User Managed or a pure RMAN-based backup strategy; that is, your backup strategy should include either User Managed backups or RMAN backups, not a combination of the two.
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User Managed backup method
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Recovery Manager (RMAN) backup method
User Managed backup method
Oracle continues to support traditional User Managed backup and recovery. With this backup method, the files that make up the database are backed up and restored using a combination of host operating system (OS) commands and SQL*Plus backup- and recovery-related capabilities.
While the plug-in’s User Managed backups offer the simplest form of backups with complete point-and-click functionality for full backups, recovering the Oracle database involves more human interaction and DBA expertise. User Managed restores begin with point-and-click restoration of the various datafiles from the backup media to the original or new destination. Restoration of the datafiles is followed by the recovery of the entire database or parts of it. With User Managed recovery, the DBA must determine what needs to be recovered and manually perform the recovery outside the plug-in by executing a series of SQL*Plus commands.
The User Managed backup method offers the simplest backup strategy at the expense of longer and more complex restores, making it more suitable for less mission-critical databases.
The backup-and-restore strategies available with the User Managed method are discussed in the Oracle Database Backup and Recovery Advanced User’s Guide and the Oracle Database Backup and Recovery User’s Guide for 11g.
While User Managed backups are available for all supported Oracle versions, they are not supported in environments where Oracle’s ASM or FRA is deployed.

Recovery Manager (RMAN) backup method

RMAN is a tool provided by Oracle that automatically integrates with sessions running on the Oracle Database Server to perform a range of backup and recovery activities. RMAN also reduces the administration work associated with your backup strategy by maintaining an extensive record of metadata about backups, archive logs, and its own activities, known as the RMAN repository. In restore operations, RMAN uses this information to eliminate the need for you to identify backup files for use in restores.
RMAN backups provide maximum reliability and flexibility when defining a backup strategy. The plug-in supports a wide range of backup types and options available with Oracle’s RMAN tool together with the ability to handle a number of recovery scenarios with less reliance on human interaction and DBA expertise. Users select what needs to be restored, the latest backup, and, if appropriate, the time, SCN, or log sequence number for PIT Recovery, and the plug-in automatically performs the recovery without further interaction.
RMAN is Oracle’s preferred solution for backup and recovery, and is the best choice for mission-critical databases. It provides maximum flexibility during the recovery process, allowing you to recover the database up to the point of failure no matter what caused the failure, whether it is a disaster, media failure, user error, or database corruption.
For a feature comparison between User Managed and RMAN backups, refer to Feature Comparison of Backup Methods in the Oracle Database Backup and Recovery Basics guide. The same guide also discusses the backup and restore strategies available with the RMAN method.
RMAN backups are available for all supported Oracle versions but are the only supported backup method for multi-instance RAC databases and Data Guard environments. In addition, Flashback Database is only available for the plug-in’s RMAN-based backups.
The following figure illustrates the RMAN-based backup process:
Figure 1. RMAN-based backup
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The user defines a backup job in the NetVault Backup WebUI.
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Plug‑in for Oracle converts the job definition into the corresponding RMAN backup commands.
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RMAN executes backup commands that read data from the Oracle database datafiles.
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RMAN uses the Oracle Media Management application programming interface (API) to store backup files on the backup device managed by the NetVault Backup Server.
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RMAN stores backup metadata in the Recovery Catalog repository.
The following figure illustrates the RMAN-based restore and recovery process:
Figure 2. RMAN-based restore and recovery
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The user defines the restore job in the NetVault Backup WebUI.
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Plug‑in for Oracle converts the job definition into corresponding RMAN restore and recovery commands.
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RMAN reads the backup metadata from the Recovery Catalog repository.
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RMAN uses the Oracle Media Management API to read the backup from the backup device managed by the NetVault Backup Server.
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RMAN restores datafiles to the Oracle server and recovers the database.

Reviewing the supported Oracle file types

Plug‑in for Oracle lets you back up the following types of Oracle database files, which are critical to the successful operation of the Oracle Instance:
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Datafiles – Datafiles are a physical file on disk that was created by Oracle Database and contain data structures such as tables and indexes. A datafile can belong to only one database, and is located either in an OS file system or in an ASM disk group.
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Control File – Control Files are binary files that record the physical structure of the database. The file includes: the database name, names and locations of associated datafiles and online redo log files, timestamps for database creation, current log sequence number, and checkpoint information. Protecting the Control File is critical to many recovery scenarios.
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Parameter File – The client-side initialization parameter file (PFILE) or the server-side initialization parameter file (SPFILE) for the Oracle database.
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Archived Redo Logs – The Oracle database copies full online redo log groups to one or more archive locations on disk, where they are collectively called the archived redo log. Individual files are referred to as archived redo log files. After a redo log file is archived, it can be backed up to other locations on disk or on tape, for long-term storage and use in future recovery operations. Without archived redo logs, your database backup and recovery options are severely limited. Your database must be taken offline before it can be backed up, and if you must restore your database from backup, the database contents are only available as of the time of the backup. Reconstructing the state of the database to a point in time is not possible without archive logs.
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External Configuration Files – The Oracle database depends on other files for operation such as network configuration files (“tnsnames.ora” and “listener.ora”) and password files. These files need to be protected for corruption or disaster recovery purposes.
It is critical that your backup strategy include all these file types to ensure recoverability from any type of failure, including media failure, data corruption, or a disaster.

Defining an RMAN backup strategy

The first step in defining an RMAN backup strategy is determining the location for the RMAN repository. The second step involves determining the types and frequency of backups that are needed to meet your recovery requirements. These steps are discussed in the following sections:
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Choosing the location for the RMAN repository
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Reviewing the RMAN Tablespace/Datafile backup types
Choosing the location for the RMAN repository
The RMAN repository is the collection of metadata about backup and recovery operations on the target database. The authoritative copy of the RMAN repository is always stored in the Control File of the target database. You can also use a Recovery Catalog (that is, an external database) to store this information.
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Control File – RMAN can conduct all necessary backup and recovery operations using just the Control File to store the RMAN repository information. This increases the importance of protecting the Control File as part of your backup strategy.
Storing the RMAN repository in the Control File is especially appropriate for small databases where installation and administration of a separate Recovery Catalog database are burdensome. The only RMAN feature that is not supported in this mode is stored scripts, which are not used by the plug-in.
When using the Control File to store the RMAN repository, Oracle highly recommends the following:
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Enable Oracle’s Control File Autobackup feature. This causes RMAN to back up the Control File automatically, and also lets RMAN restore the Control File Autobackup without access to a repository.
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Keep a record of your Oracle Database ID (DBID), which may be required to recover the database when the Control File is lost.
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Use a minimum of two multiplexed or mirrored Control Files on separate disks.
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Recovery Catalog – You can also use an external Oracle database to store the RMAN repository. This external database is known as the Recovery Catalog. While the Control File has finite space for records of backup activities, a Recovery Catalog can store a longer history. The added complexity of administering a Recovery Catalog database can be offset by the convenience of having the extended backup history available if you have to do a recovery that goes back further than the history in the Control File.
The Recovery Catalog’s version of the RMAN repository is maintained solely by RMAN. The database targeted for backup never accesses it directly because RMAN propagates the information about the database structure, archived redo logs, backup sets, and datafile copies into the Recovery Catalog from the target database’s Control File after any operation such as backup and restore.
Oracle recommends that you store the Recovery Catalog in a dedicated database. If you store the Recovery Catalog alongside other data in a database and you lose that other database, you will lose your Recovery Catalog as well. This makes recovery more difficult. Moreover, if you store the Recovery Catalog in a database that is targeted for back up, you cannot perform whole database restores for that database because the database must be in a mounted state for restores, and the plug-in will not have access to the Catalog to perform the recovery in that state.
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