Given the increasing size and widespread adoption of the Oracle enterprise database, manual backup and recovery procedures are becoming less and less suitable as a database management tool. VERITAS Software has worked closely with Oracle Corporation to develop a highly scalable and reliable array of online backup and recovery solutions for Oracle databases. Among them are:

• NetBackupTM for Oracle Advanced BLI Agent

• NetBackup Array Integration Option (for Oracle databases)

• NetBackup ServerFree Agent for Oracle

• NetBackup Instant Recovery Option

• NetBackup Shared Storage Option for use with Oracle databases

• NetBackup Database Archiver

Oracle backups can be divided into two categories:

• Cold backups, taken when the database is shut down, creating a consistent backup image (the database is in a consistent state).

• Hot backups, either full or incremental, taken while the database is online. Performing hot backups requires putting the Oracle database into a special backup mode, generating some additional redo and rollback information during the backup.

These two methods can be used in combination, with full cold backups once a week and tablespace-level hot backups on a daily basis. In addition, Oracle is continuously adding information to redo logs, which contain the transaction-by-transaction history of the database and are used to bring the database to a consistent state during a restore/recovery. The database backup process must manage all the files comprising the database, including data files, control files, parameter files and archived redo logs.

Recovering from a failure is a more complex operation, whose exact steps depend on the kind of failure experienced. Basically, there are two phases to database recovery:

• Data restoration: Identifying and restoring the appropriate data files, archived redo logs, control files and parameter files from secondary media to their appropriate location on primary disk

• Database recovery: Taking the appropriate steps in Oracle to recover the database, either to a specific point in time or to the most recent point before the failure.

Determining which files to restore is challenging, particularly if you have been performing hot backups over a long period of time without performing a cold backup. A point-in-time recovery requires different steps than an up-tothe- minute recovery. Restoring the wrong files (for example, restoring the control file when it is not necessary to do so) will cause more problems than the original outage. Determining which archive logs are required also delays recovery.

Many Oracle environments rely on the DBA to create and run backup scripts to manage their regularly scheduled Oracle backups. These scripts can perform either cold or hot backups, and will automate backups to some degree though they are in large part a manual approach. Manual methods are adequate for some installations but, as databases grow in size, manual methods become more difficult to manage and vulnerable to human error because:

• Maintaining the scripts is a manual, ongoing process. For example, as new tablespaces and data files are added to the database, the scripts must be updated.

• The scripts typically lack the robust error management and reusability of commercial software, and as such require ongoing maintenance.

• Although scripts automate backups, recovery is a manual process, requiring the presence and guidance of an experienced DBA.

• Operators still need to be available to change tapes manually during backups.

As an Oracle backup solutions partner, VERITAS has created database-specific support for Oracle databases using Oracle supplied interfaces. NetBackup for Oracle is tightly integrated with Oracle's Recovery Manager (RMAN), which is a key component of the Oracle 8.x and Oracle9i databases. These interfaces automate much of the work that previously the DBA would need to perform manually.

See the complete white paper at:

http://eval.veritas.com/downloads/pro/nbu_45fp3_oracle_backuprecovery_wp.pdf

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