Monday, May 12, 2008

Restriction of RMAN Duplicate Database

1.The target SCN for a duplicate command must be within current incarnation. Duplicate to previous incarnation is not supported. That means we can't set the target SCN for the DUPLICATE command before the most recent RESRETLOGS.

2.To run DUPLICATE database you must implicitly or explicitly allocate auxiliary channel.

3.You must be connected to both the target database and auxiliary instance. The auxiliary instance must be started with the NOMOUNT option, and the target database must be mounted or open. The target database cannot be a standby database.

4.If you need to duplicate a database when some backups of the target database do not exist then you must specify SKIP TABLESPACE. If no valid backups exist of any tablespace or datafile, then the DUPLICATE command fails.

5.While duplication you can skip any tablespace except system,undo and tablespace containing rollback segments.

6.If the target and duplicate databases reside on the same host, set the CONTROL_FILES parameter appropriately so that the DUPLICATE command does not generate an error because the target control file is in use.

7.If the target and duplicate databases share the same host, set all *_PATH and *_DEST initialization parameters appropriately so that the target database files are not overwritten by the duplicate database files.

8.You cannot set the DB_NAME parameter in the duplicate parameter file to a value different from the database name specified in the DUPLICATE command.

9.You cannot use the same database name for the target and duplicate databases when the duplicate database resides in the same Oracle home as the target.

10.If the target and duplicate databases reside on different hosts, then you must do one of the following tasks for duplication to be successful:

-Move backups and disk copies from the target host to the duplicate host to the same location as the target host so that the path names are identical

-Move backups and disk copies from the target host to the duplicate host to a new location (so that the path names are different), and then CATALOG them.

-Make sure that all backups and copies (disk or sbt) on the target host are remotely accessible from the duplicate host. Make sure that the archived redo logs are available in the expected location in the new host.

11.Duplication must be done to the same platform as the source database.

12.You cannot recover the duplicate database to the current point in time, that is, the most recent SCN. RMAN recovers the duplicate database up to or before the most recent available archived log: it cannot recover into the online redo logs.

13.If you want the duplicate filenames to be the same as the target filenames, and if the databases are in different hosts, then you must specify NOFILENAMECHECK.

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