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NetVault Plug-in for Oracle 12.3 - User Guide

Introducing Quest® 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-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

Block Media Recovery

Block Media Recovery is only available in the Oracle Enterprise Edition. This feature reduces downtime by letting you recover only the blocks that were corrupted instead of restoring and recovering the entire datafile. Block Media Recovery is most useful for physical corruption problems that involve a small, well-known number of blocks. Block-level data loss usually results from intermittent, random I/O errors that do not cause widespread data loss, and memory corruptions that get written to disk. Block Media Recovery is not intended for cases where the extent of data loss or corruption is unknown and the entire datafile requires recovery. In such cases, Datafile Media Recovery is the best solution.

You can use Block Media Recovery to recover one or more corrupt data blocks within a datafile. Block Media Recovery provides the following advantages over Datafile Media Recovery:

Without Block Media Recovery, if even a single block is corrupt, you must take the datafile offline and restore the datafile from a backup. You must apply all redo logs generated for the datafile after the backup was created. The entire file is unavailable until media recovery completes. With Block Media Recovery, only the blocks actually being recovered are unavailable during the recovery.

In addition to running the Oracle Enterprise Edition, Oracle requires the following prerequisites for Block Media Recovery to be met as defined in Performing Block Media Recovery of the Oracle Database Backup and Recovery User’s Guide.

The target database must run in ARCHIVELOG mode and be open or mounted with a current Control File.

The V$DATABASE_BLOCK_CORRUPTION view displays blocks marked corrupt by database components such as RMAN commands, ANALYZE, and SQL queries. Physical corruption, sometimes called media corruption, results in rows being added to this view. For example, the database does not recognize the block: the checksum is invalid, the block contains all zeros, or the block header is fractured.

In addition to being reported in V$DATABASE_BLOCK_CORRUPTION, block corruption is also reported in the following locations:

Results of the LIST FAILURE, VALIDATE, or BACKUP … VALIDATE command
Results of the SQL commands ANALYZE TABLE and ANALYZE INDEX
Results of the DBVERIFY utility

Performing User Managed restores

A standard User Managed restore with Plug‑in for Oracle includes the following steps:

Preparing the database for recovery

You do not have to take a complete Oracle database offline to restore selected tablespaces, but you must take each tablespace that you want to restore offline before performing the restore.

ALTER TABLESPACE <Tablespace Name> OFFLINE IMMEDIATE;

Selecting data for a restore

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On the Create Restore Job — Choose Saveset page, select Plug‑in for Oracle from the Plugin Type list.
When you select a saveset, the following details are displayed in the Saveset Information area: Job ID, job title, server name, client name, plug-in name, saveset date and time, retirement setting, Incremental Backup or not, Archive or not, and saveset size.
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Click Next.
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On the Create Selection Set page, select the data that you want to restore.
NOTE: For User Managed restores, you do not have to set any other options; the Restore Options tab does not contain any fields.
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