Validating Backups with RMAN

You can use the VALIDATE keyword of the BACKUP command to do the following:

• Check datafiles for physical and logical corruption

• Confirm that all database files exist and are in the correct locations

RMAN does not actually produce backup sets, but rather reads the specified files in their entirety, to determine whether they can be backed up and are not corrupted. In this sense, the BACKUP... VALIDATE command is similar to the RESTORE... VALIDATE command, except for backups rather than restore jobs.

If the backup validation discovers corrupt blocks, then RMAN updates the V$DATABASE_BLOCK_CORRUPTION view with rows describing the corruptions. After a corrupt block is repaired, the row identifying this block is deleted from the view.

For example, you can validate that all database files and archived redo logs can be backed up by running a command as follows:

RMAN> BACKUP VALIDATE DATABASE ARCHIVELOG ALL;

This form of the command would check for physical corruption. To check for logical corruption,

RMAN> BACKUP VALIDATE CHECK LOGICAL DATABASE ARCHIVELOG ALL;

RMAN displays the same output that it would if it were really backing up the files. If RMAN cannot validate the backup of one or more of the files, then it displays an error message. For example, RMAN may show output similar to the following:

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup command at 08/29/2001 14:33:47
ORA-19625: error identifying file /oracle/oradata/trgt/arch/archive1_6.dbf
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3

You cannot use the MAXCORRUPT or PROXY parameters with the VALIDATE option.