RESTORE

Syntax

restore::=

restoreObject::=

restoreSpecOperand::=

autoBackupOptList::=

Purpose

The primary use of RESTORE is to restore files from backups or image copies. Typically, you restore when a media failure has damaged a current datafile, control file, or archived log or prior to performing a point-in-time recovery.

There are other uses of RESTORE that do not actually restore files from backup:

• RESTORE... VALIDATE causes RMAN to select existing backups that it would use to perform a RESTORE operation, and scan them all to ensure that they are present and free of corruption.

• RESTORE... PREVIEW identifies the backups which RMAN will use to perform any RESTORE operation. Output from a RESTORE... PREVIEW is in the same format as the output of the LIST command.

• RESTORE... PREVIEW RECALL is used to request the recall of backups needed for a RESTORE operation that are stored on remote storage.

RMAN chooses which backups to restore based on the criteria that you specify. For example, you can limit the restore to backups before a given point of time (within the current incarnation) with the untilClause.

Locations of Restored Files

If you restore to the default location (that is, you do not run SET NEWNAME), then RMAN overwrites files with the same filenames. If you restore to a new location, then issue SET NEWNAME commands to rename the files and issue a SWITCH command to make the restored files current. If you do not issue SWITCH commands, then RMAN considers the restored files as valid copies for use in future restore operations.

If you do not run SET NEWNAME and RMAN detects that the default filename cannot be used (for example, because the filename is in use by another database that shares the storage), and if the file is an Oracle Managed File or is on an Automatic Storage Management disk group, then RMAN attempts to create a new file in the same location or disk group.

Channel Allocation in a Restore

If you do not manually allocate channels, then RMAN allocates all automatic channels possibly needed by the RESTORE command, subject to any restrictions imposed by the use of the DEVICE TYPE option.

For example, assume you configure 3 separate sbt channels (each with different PARMS) and then configure parallelism for DISK and sbt as follows:

CONFIGURE DEVICE TYPE DISK PARALLELISM 2;
CONFIGURE DEVICE TYPE sbt PARALLELISM 3;
CONFIGURE DEFAULT DEVICE TYPE TO sbt;

If you run RESTORE in this configuration, then RMAN allocates three sbt channels and the two preconfigured DISK channels.

Restore Failover

If a backup piece, image copy or proxy copy is inaccessible (for instance, deleted from the device) or if a block is corrupted, then the RESTORE command automatically looks for a another usable copy of this backup piece or image copy on both the same device and other devices. If no usable copies are available, then RMAN searches for prior backups. RMAN continously searches for prior usable backups until it has exhaused all possibilities.

Restore failover also occurs when restoring archivelogs for use in RECOVER, BLOCKRECOVER and FLASHBACK operations. RMAN records messages about failover due to block corruption in the alert log and trace files.

See Oracle Database Backup and Recovery Advanced User's Guide for details on restore failover.

Restoring from Encrypted Backup Sets

How RMAN handles encrypted backup sets during restore operations depends upon the encryption mode with which the backup was created.

• For transparent-mode encrypted backups, the required passwords must be available in the database wallet. This means that the same wallet that was used when creating the backup must be open, and available, when restoring it. No SET DECRYPTION command is required.

• For password-mode encrypted backups, the required passwords must be provided using SET DECRYPTION.

• For dual-mode encrypted backups, the required passwords must be available in the database wallet or provided using SET DECRYPTION.

For an overview of the encrypted backups mechanism, a guide to its use and information on choosing among the different modes of encryption, see "Encryption of Backup Sets" and the extended discussion in Oracle Database Backup and Recovery Advanced User's Guide.

The RMAN CONFIGURE, SET and SHOW commands are used to manage the RMAN backup encryption settings for your database. See the reference entries for those commands for more details.

Restoring Files in a Real Application Cluster Configuration

In a Real Application Clusters configuration, RMAN automatically restores backups, control file copies, and datafile copies from channels that can read the files on tape or a local file system. For example, if channel 1 connected to instance 1 can read log 1000 from its tape drive, but channel 2 connected to instance 2 cannot read the same log from its tape drive, then channel 1 restores the log. Autolocation is automatically enabled when the channels meet any of the following criteria:

• Different PARMS settings

• Different CONNECT strings

  See Also:

  Oracle Database Backup and Recovery Basics to learn how to restore files

Restrictions and Usage Notes

• To restore datafiles to their current location, the database must be started, mounted, or open with the tablespaces or datafiles to be restored offline. If the database is started but not mounted, then it is recommended that you only restore the control file, if necessary (refer to "Restrictions and Usage Notes for RESTORE CONTROLFILE"). To restore other files, mount the database and then continue.

  Note:

  When performing a database validation by using RESTORE ... VALIDATE, the database can be open.

• To restore to a new location, run SET NEWNAME commands to rename the datafiles and SWITCH commands to make them the current database files. If you do not use SWITCH, then the repository lists restored datafiles as datafile copies.

• If you use the FROM DATAFILECOPY option, then the allocated channels must be of DEVICE TYPE DISK.

• If you use the FROM BACKUPSET clause, then channels for the appropriate type of storage devices must be allocated for the backup sets that need to be restored. For example, if needed backups are only available on tape, and no SBT channels have been allocated, then RMAN cannot find a candidate backup set to restore, and the RESTORE command fails.

• RMAN only restores backups that were created on the same type of channels that are allocated for the RESTORE command.

  For example, if you made some backups of a datafile to DISK channels and others to sbt channels, and only a DISK channel is allocated for the RESTORE command, RMAN will not restore backups that were created on sbt channels.

• If there are no backups available for a lost datafile, RMAN will create an empty datafile with the checkpoint change as creation SCN. During recovery, all archived logs back to the creation of the datafile will be restored, and all changes during the history of the datafile will be re-applied to re-create its contents.

• If datafile names are symbolic links, that is, files pointing to other files, then the control file stores the filenames of the link files but RMAN performs I/O on the datafiles pointed to by the link files. If a link file is lost and you RESTORE a datafile without re-creating the symbolic link, then RMAN restores the datafile to the location of the link file rather than to the location pointed to by the link.

• If the database is started but not mounted in NOCATALOG mode, then the RESTORE SPFILE command requires the FROM AUTOBACKUP clause.

• If you are restoring the server parameter file and the control file in a disaster recovery situation, you cannot run RESTORE CONTROLFILE FROM AUTOBACKUP, mount this control file, and then run RESTORE SPFILE without the FROM AUTOBACKUP clause.

• Do not specify a datafile more than once in a restore job. For example, the following command is illegal because datafile 1 is both specified explicitly and implied by the SYSTEM tablespace:

  RESTORE TABLESPACE SYSTEM DATAFILE 1;
  
  

• You must have already configured a device type by using CONFIGURE (except for DISK, which is preconfigured) before specifying the DEVICE TYPE option.

• You cannot manually allocate channels and then run RESTORE DEVICE TYPE.

• When you run RESTORE with a backup control file while connected to a recovery catalog, RMAN automatically updates the control file to reflect the structure of the restored database, based on the information in the recovery catalog.

• RMAN can back up and restore dictionary-managed temporary tablespaces, but it cannot back up locally managed temporary tablespaces. It can, however, re-create locally managed temporary tablespaces after a database restore.

• RMAN does not support backup and recovery of the change tracking file. Note that database restore and recovery has no user-visible effect on change tracking. The change tracking file is re-created upon database restore and recovery, and the next incremental backup after any recovery is able to use the change-tracking file.

• If no suitable backups are available in the current incarnation of the database, then you can force RMAN to use backups from a previous incarnation. Using the CHANGE... UNAVAILABLE command, you can make all backups since the RESETLOGS that ended the incarnation unavailable. Run LIST RECOVERABLE to see valid parent incarnations.

Restrictions and Usage Notes for RESTORE CONTROLFILE

• After you restore a backup control file, you must run RECOVER DATABASE and then open the database with the RESETLOGS option.

Table 2-27 indicates the restrictions that apply in different situations involving the RESTORE CONTROLFILE command.

Restrictions and Usage Notes on RESTORE... PREVIEW

Backup media may be stored remotely, whether in a backup vaulting scenario where media is shipped to an off-site location, or in a tape library where media is on-site but not immediately accessible. Some media managers maintain information about whether the media containing specific backups is stored remotely, and make this information available to RMAN.

Backups stored remotely are marked as AVAILABLE in the RMAN repository, even though the media must be retrieved from storage before the backup can be restored. If RMAN attempts to use a remotely stored backup in a RESTORE operation, the RESTORE operation fails.

You can use RESTORE... PREVIEW to identify backups RMAN needs for a RESTORE operation that are stored on media that requires retrieval. The output of RESTORE... PREVIEW indicates whether backups are stored remotely. If a needed backup is stored remotely, your options are:

• Use CHANGE... UNAVAILABLE to prevent RMAN from selecting the needed remote backups, and attempt the RESTORE... PREVIEW operation again to see if RMAN selects another remote backup. When RMAN does not select any remote backups, you can perform your RESTORE operation.

• Use RESTORE... PREVIEW with the RECALL option. If your media manager supports this functionality, RESTORE... PREVIEW RECALL automatically requests the retrieval of the remotely stored backup media. Use RESTORE... PREVIEW again, periodically, to monitor whether the needed backups are stored locally again.

Keywords and Parameters

restore

restoreObject

restoreSpecOperand

autoBackupOptList

Examples

Restoring a Tablespace: Example This example takes a tablespace offline, restores it, then performs media recovery:

SQL "ALTER TABLESPACE users OFFLINE IMMEDIATE"; 
RESTORE TABLESPACE users; 
RECOVER TABLESPACE users;  
SQL "ALTER TABLESPACE users ONLINE";

Restoring the Control File When Using a Recovery Catalog: Example This example restores the control file to its default location, replicates it automatically to all CONTROL_FILES locations, and mounts the database:

RUN
{ # SET DBID is not necessary when connected to a recovery catalog
  STARTUP FORCE NOMOUNT;
  RESTORE CONTROLFILE;
  ALTER DATABASE MOUNT;
}

Restoring the Control File with a Tag: Example This NOCATALOG example restores the control file specified by a tag, and then mounts the database:

CONNECT TARGET /
STARTUP NOMOUNT;
SET DBID 320066378;  # required when restoring control file in NOCATALOG mode
RESTORE CONTROLFILE FROM TAG 'monday_cf_backup';
ALTER DATABASE MOUNT;

Restoring the Database with a Backup Control File: Example This example restores the control file to a temporary location, replicates it to all control file locations specified in the CONTROL_FILES initialization parameter, and then restores and recovers the database:

CONNECT TARGET /
STARTUP NOMOUNT;
SET DBID 320066378;  # required when restoring control file in NOCATALOG mode
RUN
{
  ALLOCATE CHANNEL c1 DEVICE TYPE sbt;
  RESTORE CONTROLFILE FROM AUTOBACKUP;
  ALTER DATABASE MOUNT;
  RESTORE DATABASE;
  RECOVER DATABASE;
}
ALTER DATABASE OPEN RESETLOGS;

Restoring Archived Redo Logs to a New Location: Example This example restores all archived redo logs to the /oracle/temp_restore directory:

RMAN> RUN
{ 
  SET ARCHIVELOG DESTINATION TO '/oracle/temp_restore';
  RESTORE ARCHIVELOG ALL;
}

Restoring a Control File Autobackup to a Nondefault Location: Example This example restores the latest control file autobackup made on or before June 23, 2000 with a nondefault format of PROD_CF_AUTOBACKUP_%F. It starts searching for backups with a sequence number of 20, and searches backward for 5 months:

RMAN> SET DBID 320066378;  # required when restoring control file in NOCATALOG mode
RMAN> RUN
{
  SET UNTIL TIME '23-JUN-2001 00:00:00';
  SET CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE sbt TO 'prod_cf_autobackup_%F';
  ALLOCATE CHANNEL CHANNEL_1 DEVICE TYPE sbt;
  RESTORE CONTROLFILE TO '/tmp/autobackup_20001002.dbf' FROM AUTOBACKUP 
    MAXSEQ 20 MAXDAYS 150;
}

Restoring the Server Parameter File to Current Location: Example The following series of commands restores the current server parameter file in NOCATALOG mode:

rman TARGET /
RMAN> SET DBID 1447326980 # set dbid to dbid of target database
RMAN> STARTUP FORCE NOMOUNT; # start instance with dummy SPFILE
RMAN> RUN
{
  ALLOCATE CHANNEL c1 DEVICE TYPE sbt;
  RESTORE SPFILE FROM AUTOBACKUP; # FROM AUTOBACKUP needed in NOCATALOG mode
}
RMAN> STARTUP FORCE; # start with restored SPFILE and open database

Identifying Needed Backups with RESTORE... PREVIEW: Example The following example shows the results of a RESTORE PREVIEW, which identifies the backupsets RMAN selects for use in restoring archivelogs from backup. (Note that in this output, one of the archivelog backups is stored remotely.)

RMAN> restore archivelog all preview;
 
Starting restore at 10-JUN-05
using channel ORA_DISK_1
using channel ORA_SBT_TAPE_1
 
 
List of Backup Sets
===================
 
BS Key  Size       Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
31      12.75M     SBT_TAPE    00:00:02     10-JUN-05     
        BP Key: 33   Status: AVAILABLE  Compressed: NO  Tag: TAG20050610T152755
        Handle: 15gmknbs   Media: /v1,15gmknbs
 
  List of Archived Logs in backup set 31
  Thrd Seq     Low SCN    Low Time  Next SCN   Next Time
  ---- ------- ---------- --------- ---------- ---------
  1    1       221154     06-JUN-05 222548     06-JUN-05
  1    2       222548     06-JUN-05 222554     06-JUN-05
  1    3       222554     06-JUN-05 222591     06-JUN-05
  1    4       222591     06-JUN-05 246629     07-JUN-05
  1    5       246629     07-JUN-05 262451     10-JUN-05
 
BS Key  Size       Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
32      256.00K    SBT_TAPE    00:00:01     10-JUN-05     
        BP Key: 34   Status: AVAILABLE  Compressed: NO  Tag: TAG20050610T153105
        Handle: 17gmknhp_1_1   Media: /v1,17gmknhp_1_1
 
  List of Archived Logs in backup set 32
  Thrd Seq     Low SCN    Low Time  Next SCN   Next Time
  ---- ------- ---------- --------- ---------- ---------
  1    6       262451     10-JUN-05 262547     10-JUN-05
  1    7       262547     10-JUN-05 262565     10-JUN-05
 
List of remote backup files
============================
        Handle: 15gmknbs   Media: /v1,15gmknbs

Recalling Vaulted Backups from Remote Storage with RESTORE... PREVIEW RECALL: Example When used with a media manager that reports information about remote storage of backups and supports recalling vaulted backups, the following command requests that any media needed in the restore of archivelogs from backup be recalled from remote storage:

RMAN> RESTORE ARCHIVELOG ALL PREVIEW RECALL;
Starting restore at 10-JUN-05
using channel ORA_DISK_1
using channel ORA_SBT_TAPE_1
 
 
List of Backup Sets
===================
 
BS Key  Size       Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
31      12.75M     SBT_TAPE    00:00:02     10-JUN-05     
        BP Key: 33   Status: AVAILABLE  Compressed: NO  Tag: TAG20050610T152755
        Handle: 15gmknbs   Media: /v1,15gmknbs
 
  List of Archived Logs in backup set 31
  Thrd Seq     Low SCN    Low Time  Next SCN   Next Time
  ---- ------- ---------- --------- ---------- ---------
  1    1       221154     06-JUN-05 222548     06-JUN-05
  1    2       222548     06-JUN-05 222554     06-JUN-05
  1    3       222554     06-JUN-05 222591     06-JUN-05
  1    4       222591     06-JUN-05 246629     07-JUN-05
  1    5       246629     07-JUN-05 262451     10-JUN-05
 
BS Key  Size       Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
32      256.00K    SBT_TAPE    00:00:01     10-JUN-05     
        BP Key: 34   Status: AVAILABLE  Compressed: NO  Tag: TAG20050610T153105
        Handle: 17gmknhp_1_1   Media: /v1,17gmknhp_1_1
 
  List of Archived Logs in backup set 32
  Thrd Seq     Low SCN    Low Time  Next SCN   Next Time
  ---- ------- ---------- --------- ---------- ---------
  1    6       262451     10-JUN-05 262547     10-JUN-05
  1    7       262547     10-JUN-05 262565     10-JUN-05
 
Initiated recall for the following list of remote backup files
==========================================================
        Handle: 15gmknbs   Media: /v1,15gmknbs
Finished restore at 10-JUN-05

Validating a Restore with RESTORE VALIDATE: Example The following example illustrates using RESTORE... VALIDATE to confirm that backups required for the restore of datafile 1 are present on disk or tape, readable, and not corrupted:

RMAN> RESTORE DATAFILE 1 VALIDATE;

Starting restore at 10-OCT-03
using channel ORA_DISK_1

channel ORA_DISK_1: starting validation of datafile backupset
channel ORA_DISK_1: restored backup piece 1
piece handle=/disk1/oracle/work/v1/0pf3hr3o_1 tag=FOURTH_INC
channel ORA_DISK_1: validation complete
Finished restore at 10-OCT-03