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NetVault Plug-in for Oracle 13.0 - User Guide

Introducing Quest® NetVault® 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-in in a failover cluster environment Using the plug-in with Oracle Data Guard Using the plug-in with Oracle Container Databases (CDBs) and Pluggable Databases (PDBs) Troubleshooting

How RMAN backups are selected for use in recovery operations

When the plug-in performs RMAN-based restores, RMAN itself is performing the restores and recovery operations. RMAN uses the record of available backups in the RMAN repository to select the best available backups for use in the restore operation. This step simplifies the recovery process by eliminating the need for less-experienced personnel to determine the order in which backups should be restored.

Choosing between Incremental Backups and Redo Logs

If RMAN has a choice between applying an Incremental Backup or applying redo logs to the restored datafiles to meet a recovery objective, it always chooses an Incremental Backup. If overlapping levels of Incremental Backup are available, RMAN automatically chooses the one covering the longest period.

RMAN automatically restores the datafiles that it needs from available backups, applies Incremental Backups to the datafiles if they are available, and then applies archive logs.

Choosing the restore source

When FRA is enabled, the plug-in lets you define a media destination strategy that balances requirements while speeding up restores by specifying the Destination Backup Options on the Backup Options tab. These options let you select the destination for the backup. They include:

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NetVault Media Manager
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Disk (Backup to FRA)
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Both NetVault Media Manager and Disk (Backup to FRA then Backup FRA to NetVault Media)

The plug-in provides you with the option during the restore process to define the Restore Source or location that RMAN should use as the source for the restore. This option lets you speed up restores by ensuring that RMAN restores from the FRA or from the NetVault media. With this option, you can:

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Restore from the FRA even if the backup is also available on NetVault media such as disk-based media, VTL, or tape.
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Restore from the NetVault media when the FRA is suspected to have a media failure or data corruption and you do not want to risk restarting the restore and recovery process due to RMAN’s inability to restore from the FRA.

Additionally, you can use these same Restore Source options when you have performed CLI-based backups to Disk by allocating a channel to Disk but you want to use the plug-in to perform the restore.

The following Restore Source options are available:

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NetVault Media Manager: When selected, RMAN opens an “SBT_TAPE” channel and reads the backup files from the backup media that is managed by NetVault and specified in the Device options section of the Target tab. Select this option if an FRA-backup-destination strategy has not been implemented or the Backup Destination of NetVault Media Manager was selected for all backups.
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Disk (Restore from FRA or Disk): When selected, RMAN only opens a DISK device type and restores the backup files from the FRA or the OS-specific directory specified when configuring RMAN’s DISK device type. This option is the default.
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Both NetVault Media Manager and Disk (Restore from both NetVault Media and (FRA or Disk)): When selected, RMAN opens an “SBT_TAPE” channel and a DISK channel, which allows RMAN the flexibility to choose the best source for the recovery files. Select this option if your backup destination strategy includes the Both NetVault Media Manager and Disk option or you have chosen to store backup recovery files in the FRA while performing Flash Recovery Area Backups on a different, independent schedule.

Datafile media recovery

Datafile media recovery is the application of online logs, archived redo logs, or Incremental Backups to a restored datafile to update it to the current time or some other specified time. Datafile media recovery, often called Recovery, is either Complete Recovery or Point-in-Time (PIT) Recovery, also called Incomplete Recovery. PIT Recovery is one way to respond to a data loss caused by a user error, such as dropping a table, or logical corruption that goes unnoticed for some time.

Complete Recovery vs. Point-in-Time (PIT) Recovery

Complete Recovery recovers the database to the most recent time without the loss of any committed transactions. With PIT Recovery, you can recover the database to a specific point. The plug-in supports PIT Recovery based on time, log sequence number, or system change number. Currently, the plug-in supports only Database Point-in-Time Recovery (DBPITR).

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System Change Number (SCN) Based Point-in-Time Recovery: When an SCN is specified during PIT Recovery, RMAN recovers up to, but not including, the specified SCN. For example, if SCN 1000 is specified, recovery up to SCN 999 is performed.
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Log Sequence Number (LSN) Based Point-in-Time Recovery: When the exact time of the data corruption or failure is not known, specifying a Log Sequence Number that contains the target SCN is a viable option. RMAN recovers through the specified log. V$LOG_HISTORY can be queried to view the logs that have been archived to identify the appropriate log sequence number and thread.
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Time Based Point-in-Time Recovery: Time-based PIT Recovery is useful when the time that the data corruption occurred is known. For example, if a developer dropped a table at 6:00 a.m., PIT Recovery can be performed with a stop time of 5:55 a.m. The plug-in recovers up to, but not including, the specified time.

For more information on PIT Recovery and database incarnations, see Performing Database Point-in-Time Recovery in the Oracle Database Backup and Recovery Basics guide.

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