NetVault Plug-in for Oracle 12.3

Determining which datafiles require recovery

When a media failure or data corruption has occurred, you can use the following SQL*Plus query to determine which datafiles need recovery. This command works only when the database is in an OPEN state:

SELECT FILE#, ERROR, ONLINE_STATUS, CHANGE#, TIME FROM V$RECOVER_FILE;

Recovering datafiles and archive logs

After identifying the damaged datafiles, restore the last Full Backup of the datafiles and the backup of all archive logs generated since the last backup until the target recovery time. When you restore the datafiles, the existing files are replaced with the backed-up copy. Conversely, when you restore the archive logs, these files are copied to the original location so that they are available to the database during the recovery process.

The recovery of the damaged datafiles and the archive logs includes the following steps:

Connect to the database with SYSDBA privileges by using the SQL*Plus utility.

SQLPLUS SYS AS SYSDBA

If the database is open, use the following command to alter all the tablespaces that you want to recover:

ALTER TABLESPACE <Tablespace Name> OFFLINE;

Use the plug-in to restore the damaged datafiles from the latest User Managed Full Backup saveset.

To restore datafiles to a different location, specify the new path during restore.

Use the plug-in to restore all the archive logs backups that have been completed since the User Managed Full Backup.

Restore the logs to the primary destination directory. If space is limited, use the Rename option to restore the logs to a different directory. For more information, see Using advanced User Managed restore procedures.

After the restoration is complete, use SQL*Plus to perform the recovery manually by issuing the following command for every tablespace that needs recovering:

RECOVER TABLESPACE <Tablespace Name>

Alter the recovered tablespaces online with the following SQL*Plus command:

ALTER TABLESPACE <Tablespace Name> ONLINE;

Restoring Control Files

You can recover a Control File using one of the following options:

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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, see 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 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 box. 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:

Use the plug-in to restore the Control File from the latest Control File backup.

The plug-in restores it to the Control File Save Filename (Full Path). The restored file has a “.SAV” extension.

Connect to the database with SYSDBA privileges by using the SQL*Plus utility.

SQLPLUS SYS AS SYSDBA

Shut down the database.

Rename and copy this restored file to the Control File name and location specified in the Oracle parameter file.

Mount the database.

STARTUP MOUNT;

To recover the database to a point equivalent to the current SCN stored in the datafiles, perform the recovery by using the USING BACKUP CONTROLFILE command.

More 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 contains 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, see Restoring a Backup Control File to the Default Location in the Oracle Database Backup and Recovery Advanced User’s Guide.

After recovery is finished, open the database with the RESETLOGS option.

ALTER DATABASE OPEN RESETLOGS;