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Oracle® Database Backup and Recovery Reference
10g Release 2 (10.2)

Part Number B14194-02
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DUPLICATE

Syntax

duplicate::=

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dupOptionList::=

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dupsbyOptionList::=

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logSpec::=

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sizeSpec::=

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Purpose

To use backups (backup sets or image copies) of the target database to create either of the following:

To create a standby database with the DUPLICATE command you must specify the FOR STANDBY option. The DUPLICATE ... FOR STANDBY command creates the standby database by restoring a standby control file, mounting the standby control file, and then restoring and recovering backups of the target datafiles. The standby database is left mounted after duplication is complete. Note that backups of the standby database are interchangeable with backups of the primary database.

When duplicating a database that is currently in NOARCHIVELOG mode, recovery occurs with the NOREDO option. Hence, if incremental backups exist, RMAN applies only these backups to the restored files during recovery. For databases in ARCHIVELOG mode, DUPLICATE recovers by default up to the last archived redo log generated at the time the command was executed, or until a time specified with a SET UNTIL clause.


See Also:

Oracle Database Backup and Recovery Advanced User's Guide to learn how to create a duplicate database with the DUPLICATE command

Oracle Data Guard Concepts and Administration to learn how to create, manage, and back up a standby database


Restrictions and Usage Notes

These restrictions apply to all uses of the DUPLICATE command (both for creation of a standby database and creation of a nonstandby duplicate database):

The following restrictions and notes apply when you use the DUPLICATE command with the FOR STANDBY option:

Keywords and Parameters

duplicate

Syntax Element Description
FOR STANDBY Specifies that database being duplicated is to be used as a standby database. RMAN restores the most recent files, unless SET UNTIL is specified. If DORECOVER is specified, then RMAN also recovers database. RMAN always leaves standby database in mounted state after executing DUPLICATE command.
dupsbyOptionList Specifies options that only apply when creating a standby database.
DORECOVER Specifies that RMAN should recover the database after creating it. If you specify an untilClause, then RMAN recovers to the specified point and leaves the database mounted.
NOFILENAMECHECK Prevents RMAN from checking whether target datafiles sharing the same names as the duplicated files are in use. Note that the NOFILENAMECHECK option is required when the standby and primary datafiles and logs have identical filenames.

See Also: The description in dupOptionList

TO 'database_name' Specifies the name of the duplicate database. The name should match the name in the initialization parameter file of the duplicate database or the database signals an error when creating the control file.

dupOptionList

Syntax Element Description
dupOptionList Specifies options that apply when creating a duplicate database not intended for use as a standby database.
DEVICE TYPE deviceSpecifier Allocates automatic channels for the specific deviceSpecifier only (for example, DISK or sbt). This option is valid only if you have configured automatic channels and have not manually allocated channels. For example, if you CONFIGURE automatic disk and tape channels, and if you run DUPLICATE...DEVICE TYPE DISK, then RMAN allocates only disk channels.

See Also: "deviceSpecifier"

fileNameConversionSpec
Specifies one or more patterns to map original to duplicate filenames.

Note that this parameter overrides the initialization parameter DB_FILE_NAME_CONVERT (if it is set). If a file in the specification list is not affected by the conversion parameter in DUPLICATE, then you must rename it by other means, such as SET NEWNAME.

See Also: "fileNameConversionSpec"

LOGFILE logSpec Specifies the online redo logs when creating a nonstandby duplicate database. The syntax is the same used in the LOGFILE option of the CREATE DATABASE statement.

Refer to the description of logSpec for the legal options.

NOFILENAMECHECK Prevents RMAN from checking whether target datafiles sharing the same names as the duplicated files are in use. The user is responsible for determining that the duplicate operation will not overwrite useful data.

This option is necessary when you are creating a duplicate database in a different host that has the same disk configuration, directory structure, and filenames as the host of the target database. For example, assume that you have a small database located in the /dbs directory of host1:

/oracle/dbs/system_prod1.dbf 
/oracle/dbs/users_prod1.dbf 
/oracle/dbs/tools_prod1.dbf 
/oracle/dbs/rbs_prod1.dbf 

Assume that you want to duplicate the database in machine host2, which has the same file system /oracle/dbs/*, and you want to use the same filenames in the duplicate database as in the primary. In this case, specify the NOFILENAMECHECK option to avoid an error message. Because RMAN is not aware of the different hosts, RMAN cannot determine automatically that it should not check the filenames.

OPEN RESTRICTED Enables a restricted session in the duplicate database by issuing the following SQL statement: ALTER SYSTEM ENABLE RESTRICTED SESSION. RMAN issues this statement immediately before the duplicate database is opened.
PFILE = 'filename' Specifies a client-side initialization parameter used by the auxiliary instance. RMAN automatically shuts down and restarts the auxiliary instance during duplication. If the auxiliary does not use a server-side parameter file in the default location, you must specify the client-side parameter file that RMAN should use when starting the auxiliary instance. Otherwise, you do not need to specify PFILE.
SKIP READONLY Excludes datafiles in read-only tablespaces from the duplicate database.

Note: A record for the skipped read-only tablespace still appears in DBA_TABLESPACES. By using this feature, you can activate the read-only tablespace later. For example, you can store the read-only tablespace data on a CD-ROM, then mount the CD-ROM later and view the data.

SKIP TABLESPACE 'tablespace_name' Excludes the specified tablespace from the duplicate database. Note that you cannot exclude the SYSTEM tablespace, undo tablespaces, and tablespaces with rollback segments.
untilClause
Sets the end point for incomplete recovery of the duplicate database. You can achieve the same result by running SET UNTIL before the DUPLICATE command.

See Also: "untilClause"


logSpec

Syntax Element Description
logSpec Specifies the online redo logs when creating a nonstandby duplicate database. If you do not specify LOGFILE, then RMAN uses LOG_FILE_NAME_CONVERT if it is set. If neither LOGFILE nor LOG_FILE_NAME_CONVERT is set, then RMAN uses the original target log filenames for the duplicate files. You must specify the NOFILENAMECHECK option in this case.

See Also: Oracle Database SQL Reference for CREATE DATABASE syntax

'filename' SIZE integer Specifies the filename of the online redo log member and the size of the file in kilobytes (K) or megabytes (M). The default is in bytes.
REUSE Allows the database to reuse an existing file. If the file already exists, then the database verifies that its size matches the value of the SIZE parameter. If the file does not exist, then it is created.
GROUP integer Specifies the group containing the online redo log members.

dupsbyOptionList

Syntax Element Description
dupsbyOptionList Specifies options that only apply when creating a standby database.
DORECOVER Specifies that RMAN should recover the database after creating it. If you specify an untilClause, then RMAN recovers to the specified point and leaves the database mounted.
fileNameConversionSpec
Specifies how to convert original datafile names to new datafile names in the standby database.

See Also:"fileNameConversionSpec"

NOFILENAMECHECK Prevents RMAN from checking whether target datafiles sharing the same names as the duplicated files are in use. Note that the NOFILENAMECHECK option is required when the standby and primary datafiles and logs have identical filenames.

See Also: The description in dupOptionList


Examples

Setting New Filenames Manually: Example This example assumes that the target datafiles are on host1 in directory /h1/oracle/dbs/trgt. You wish to duplicate the database to newdb on host2 in the directory /h2/oracle/oradata/newdb. The DUPLICATE command uses backup sets stored on tape to duplicate the target database to database newdb, and recovers it to a point 24 hours ago:

RUN
{  
  ALLOCATE AUXILIARY CHANNEL newdb1 DEVICE TYPE sbt; 
  DUPLICATE TARGET DATABASE TO newdb
    DB_FILE_NAME_CONVERT=('/h1/oracle/dbs/trgt/','/h2/oracle/oradata/newdb/')
    UNTIL TIME 'SYSDATE-1'  # specifies incomplete recovery
    SKIP TABLESPACE cmwlite, drsys, example   # skip desired tablespaces
    PFILE = ?/dbs/initNEWDB.ora
    lOGFILE
      GROUP 1 ('?/oradata/newdb/redo01_1.f', 
               '?/oradata/newdb/redo01_2.f') SIZE 200K, 
      GROUP 2 ('?/oradata/newdb/redo02_1.f', 
               '?/oradata/newdb/redo02_2.f') SIZE 200K 
      GROUP 3 ('?/oradata/newdb/redo03_1.f',
               '?/oradata/newdb/redo03_2.f') SIZE 200K REUSE;
}

Reusing the Target Filenames: Example This example assumes the following:

CONNECT TARGET
CONNECT AUXILIARY SYS/aux_pwd@newdb
DUPLICATE TARGET DATABASE TO ndbnewh 
  LOGFILE 
    '?/dbs/log_1.f' SIZE 200K,
    '?/dbs/log_2.f' SIZE 200K 
  SKIP READONLY 
  NOFILENAMECHECK;

Creating a Standby Database: Example This example creates a standby database on a remote host with the same directory structure as the primary host. In this example, the NOFILENAMECHECK option is specified because the standby and primary datafiles and logs have the same names. Note that an automatic auxiliary channel is already configured, so you do not need to manually allocate a channel:

DUPLICATE TARGET DATABASE FOR STANDBY
  NOFILENAMECHECK;