Use
When making database backups, you must regularly perform a verify.
If you fail to verify backups, you might find that a backup cannot be used in the event of a database restore. Even if a backup is reported as successfully completed, this does not mean that it is always error-free.
There are the following types of verify:
This verify checks the backup media (that is, usually tape). It checks the size of the backup files and whether the data can be read. In some cases, it also compares the backed-up data with the contents of the database byte-by-byte.
This verify checks the database itself block-by-block.
At least once in every
backup cycle, you must perform both types of verify. If possible, perform verify once a week, or even for every backup.Integration
Prerequisites
Features
Verify of Backups with BRBACKUP
This type of verify only checks the backup tape readability. The method and extent of a
BRBACKUP verify differs according to whether the backup is online or offline:After the backup the files are copied back to a temporary directory,
After the backup the files are copied back to a temporary directory,
For more information, see
brbackup -w|-verify.Independent Verify of Backups with BRRESTORE
This type of verify with
BRRESTORE only checks the backup tape readability, separately from the backup, at a later time if you want. You can also perform this type of verify on another computer.BRRESTORE only checks whether the backup can be read and its size, not the contents. The files are only read, not restored.
For more information, see
brrestore -w|-verifyVerify of Backups with BRARCHIVE
This type of verify with
BRARCHIVE only checks the backup tape readability. The extent of the check on archived offline redo log files depends on the type of BRARCHIVE backup:The backed-up files are restored and compared with the originals byte by byte.
The file sizes of the archived offline redo log files are checked. Since the originals were deleted, a check on the contents is not possible.
For more information, see
-brarchive -w|-verifyVerify of Backups with Oracle DBVERIFY
The Oracle DBVERIFY tool is available for both types of verify, that is, backup tape readability (but without a byte-by-byte comparison) and database block consistency. This means you can recognize errors early (for example, ORA-1578), before they lead to the termination of a program in an application that accesses the blocks.
You can use DBVERIFY as follows:
brbackup -w use_dbv
brbackup -w only_dbv
Any number of these verify processes can run in parallel, using parameter
exec_parallel, option -e.brrestore -w use_dbv
The restore implicitly checks the readability of the backup.
Verify of BACKINT Backups
You can verify third-party backups using the BACKINT interface. This function confirms that backups are known to the external backup tool (that is, confirmation) and they are accepted when restoring. In this case there is no physical data check on the backup medium. Only an internal catalog of BACKINT backups of the backup tool is checked (that is, logical verification). Verifications using Oracle DBVERIFY are no longer supported in this context.
If you want to include verification of the internal Oracle block
consistency with DBVERIFY, you can check the database directly without
starting the backup. To do this, call BRBACKUP as follows:
brbackup -w only_dbv
From Release 4.5A, the external backup tool – that is,
backup_dev_type = rman_util – can also be accessed using the Oracle Recovery Manager (RMAN). This gives you a complete range of functions for verification:You can also use BR programs from Release 4.5 for RMAN backups for lower SAP releases. Oracle 8.0 is required in this case. For more information, see Note 12741.
Of course, you can perform BACKINT backup verification directly using the backup tool (if supported). Some backup tools offer special parameters in the BACKINT parameter file,