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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

Restoring Control Files

You can recover a Control File using one of the following options:
•
Restoring a Lost Copy of a Multiplexed Control File – Use this procedure to recover a database if a permanent media failure has damaged one or more Control Files of a database, and at least one Control File has not been damaged by the media failure. For more information, refer to Restore Lost Copy of a Multiplexed Control File in the Oracle Database Backup and Recovery Advanced User’s Guide or to Responding to the Loss of a Subset of the Current Control Files in the Oracle Database Backup and Recovery User’s Guide for Oracle 11g.
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Restoring a Control File from Backup After Loss of All Current Control Files – Use this procedure to restore a Backup Control File if a permanent media failure has damaged all Control Files of a database and you have a backup of the Control File.
Restoring a Control File from backup after loss of all current Control Files
When a Control File is inaccessible, you can start the Instance, but not mount the database. If you attempt to mount the database when the Control File is unavailable, you will get the following error message:
ORA-00205: error in identifying Control File, check alert log for more info
You cannot mount and open the database until the Control File is accessible.
The plug-in saves a copy of the snapshot of the Control File to the Control File Save Filename (Full Path) specified on the Add (or Edit) Oracle Database dialog. You can copy the Control File from this location if you lose all current Control Files. If the snapshot is not available in the Control File Save Filename (Full Path), you can restore it from the backup by performing the following steps:
1
Use the plug-in to restore the Control File from the latest Control File backup.
The plug-in will restore it to the Control File Save Filename (Full Path). The restored file will have a “.SAV” extension.
2
Connect to the database with SYSDBA privileges via the SQL*Plus utility.
SQLPLUS SYS AS SYSDBA
3
Shut down the database.
4
Rename and copy this restored file to the Control File name and location specified in the Oracle parameter file.
5
Mount the database.
STARTUP MOUNT;
6
To recover the database to a point equivalent to the current SCN stored in the datafiles, perform the recovery via the USING BACKUP CONTROLFILE command.
Additional recovery is needed to recover the database to the point that equals the current SCN stored in the datafiles. For example, when restoring from an older backup, the Control File will contain a different SCN from the current datafiles, so it does not know which log sequence is archived and which is not.
For example:
RECOVER DATABASE USING BACKUP CONTROLFILE;
For more information on restoring a Backup Control File, refer to Restoring a Backup Control File to the Default Location in the Oracle Database Backup and Recovery Advanced User’s Guide.
7
After recovery is finished, open the database with the RESETLOGS option.
ALTER DATABASE OPEN RESETLOGS;

Understanding RMAN recovery

Review the following sections regarding RMAN recovery:
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How RMAN backups are selected for use in recovery operations
•
Choosing between Incremental Backups and Redo Logs
•
Choosing the restore source
•
Datafile media recovery
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Block Media Recovery
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 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 best balances business 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:
•
Tape (Backup to NetVault Backup Media)
•
Disk (Backup to FRA)
•
Both Tape and Disk (Backup to FRA then Backup FRA to NetVault Backup 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 lets you speed up restores by ensuring that RMAN restores from the FRA even if the backup is also available on NetVault Backup media such as disk-based media, VTL, or tape, or ensuring that RMAN restores from the NetVault Backup 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:
•
Tape (Restore from NetVault Backup Media – When selected, RMAN opens an “SBT_TAPE” channel and reads the backup files from the backup media that is managed by NetVault Backup 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 Tape was selected for all backups.
•
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 is the default option.
•
Both Tape and Disk (Restore from both NetVault Backup 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 Tape 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.
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