Optimizing and deduplicating stream-based and proxy copy Oracle backups
NetBackup enables you to perform optimized deduplication of Oracle databases. You can perform either a stream-based backup or a proxy copy backup.
Veritas recommends that you perform a proxy copy if the database consists of many small tablespaces. A proxy copy is also recommended if the DBA or the backup administrator does not want to set FILESPERSET=1.
To configure a proxy copy Oracle backup, you need to edit the RMAN script and configure NetBackup for Oracle.
See Editing the RMAN script and configuring NetBackup for Oracle for a proxy copy backup.
For stream-based backups, Veritas recommends that you specify FILESPERSET=1 for all Oracle database backups. When FILESPERSET=1 is specified, Oracle generates the backup set identically each time. The backup set is generated with the same data from the same files in the same sequence each time the database is backed up. This uniformity ensures better deduplication. In addition, when FILESPERSET=1 is in effect, Oracle does not perform multiplexing, so Oracle includes only one file in each backup set. If FILESPERSET is specified with a number other than 1, Oracle groups files together unpredictably and deduplication rates suffer. You may also want to increase the number of channels that are allocated to the backup, if possible.
It is recommended that you test your database backups by running both stream-based backups and proxy copy backups. Measure the deduplication rates and the backup times, and see which method fits best in your environment. The Oracle database files themselves benefit the most from deduplication. Typically, the archive logs and the control files are unique, so they benefit less from deduplication.
Deduplication performs best when used in the following ways:
| Stream deduplication | The Oracle Intelligent Policy detects both ASM and non-ASM environments to generate the correct backup scripts ensuring good deduplication rates. In a non-ASM environment, scripts are generated that are a non-snapshot proxy backup. In an ASM environment, scripts are generated that set FILESPERSET=1 if this command has not been modified in a backup policy. You may need to create a custom script for your environment. However, in most situations, the Oracle Intelligent Policy creates the script that is needed for your environment. |
Snapshot deduplication | When you use snapshot deduplication, nothing changes and NetBackup proxy snapshot backup is performed. If ASM is detected, an error is displayed. Snapshot backup is not allowed in an ASM environment. |
Note:
In OIP when deduplication storage is used and a stream-based backup is selected, the policy overrides and attempts to perform a proxy backup. The override is attempted if NO ASM storage is found in the database. The ORACLE_OVERRIDE_DATA_MOVEMENT setting in the bp.conf file can be used to override this behavior.
Set ORACLE_OVERRIDE_DATA_MOVEMENT=1 to always do streaming.
Set ORACLE_OVERRIDE_DATA_MOVEMENT=2 to always do proxy.
Set ORACLE_OVERRIDE_DATA_MOVEMENT=>2 to maintain standard behavior.
On UNIX you can edit the /usr/openv/netbackup/bp.conf file.
On Windows you can use the bpsetconfig command (install_path\NetBackup\bin\admincmd\bpsetconfig) on the server to set the client's configuration. See the following example:
bpsetconfig -h myoracleclient
ORACLE_OVERRIDE_DATA_MOVEMENT = 1
For information about the backup methods, see the following: