An image copy is an exact copy of a single datafile, archived redo log file, or control file. Image copies are not stored in an RMAN-specific format. They are identical to the results of copying a file with operating system commands. RMAN can use image copies during RMAN restore and recover operations.

RMAN BACKUP AS COPY command is used to create image copies. Following example create an image copy of tablespace INET_STAR.

BACKUP AS COPY
TABLESPACE INET_STAR;

Following example makes full database Backup to disk as image copy

BACKUP AS COPY
DEVICE TYPE DISK
DATABASE;

Set Format for RMAN Image Copy

FORMAT variables are also used to specify the names of image copies. if no FORMAT is specified with the BACKUP DATABASE command, then RMAN uses the default format %U. You can also name the output copies with the DB_FILE_NAME_CONVERT parameter of the BACKUP command.

In the following example DB_FILE_NAME_CONVERT is used to convert file name with new loction.

BACKUP AS COPY
TABLESPACE users
DB_FILE_NAME_CONVERT
('/maindisk/oradata/users','/backups/users_ts');

If you run a RESTORE command, then RMAN restores a datafile file to its original location by copying an image copy backup to that location. Image copies are chosen over backup sets.

If you need to restore and recover a current datafile, and if you have an image copy available on disk, then you do not need to have RMAN copy the image copy back to its old location. Instead, you can use the image copy in place as a replacement for the datafile to be restored.

Advantages of RMAN Image Copy

There are a couple of distinct advantages for using RMAN to perform image copy backups:

  • First, the backup is automatically recorded in the RMAN repository.
  • Second, all blocks are checked for corruption as they are read and copied to the backup destination.
  • Another side benefit to making image copies is that the copies can be used "as is" outside of RMAN if, for some reason, a recovery operation must occur outside of RMAN.
  • Image copies can only be created on DISK device types.

 

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