The Duplex Copy function

With Data Protection for Oracle, you can use the Oracle Server Duplex backup feature to make up to four exact duplicate copies of a backup. The backup can then be stored on different backup media.

About this task

A different management class is required for each backup copy. By default, the primary management class is the default management class on the policy domain that is defined for the Data Protection for Oracle node.
Note: It might be necessary to define the Oracle parameter value (BACKUP_TAPE_IO_SLAVES=TRUE) in the init.ora file of the target database for Data Protection for Oracle to use the duplex copy feature. Refer to your Oracle documentation about the use of this Oracle parameter.

For example, to create four backup copies:

Procedure

  1. Specify the following option in the RMAN backup script: 
    set duplex=4
  2. Define the following options in the tdpo.opt file:
    • tdpo_mgmt_class_2
    • tdpo_mgmt_class_3
    • tdpo_mgmt_class_4
  3. Run the RMAN backup script.

Results

The following backup behavior occurs:

  • The first backup copy is bound to the default management class to which the node is registered.
  • The second backup copy is bound to the management class defined by the tdpo_mgmt_class_2 option.
  • The third backup copy is bound to the management class defined by the tdpo_mgmt_class_3 option.
  • The fourth backup copy is bound to the management class defined by the tdpo_mgmt_class_4 option.
Note: Take note of the considerations provided:
  • The duplex copy feature does not use include statements. It uses the management classes that are specified in the tdpo.opt file.
  • You receive an error message if you specify set duplex =4 in the RMAN backup script and do not define enough tdpo_mgmt_class options in the tdpo.opt file.
  • To place duplicate copies on different media:
    • Make sure that the storage pool information for each backup copy group within the management classes is not the same.
    • Make sure that backups from these different storage pools are not moved to the same storage pool later.
  • Duplicate data is sent across the network.
  • If you specify set duplex =4 and allocate one channel in the RMAN backup script, RMAN will start four sessions to the Tivoli® Storage Manager server. Likewise, if you specify set duplex =4 and allocate two channels in the RMAN backup script, RMAN will start eight sessions to the Tivoli Storage Manager server.
  • The duplex copy feature sends the backup copies simultaneously. If the backup destination is tape, the number of sessions is a multiple of the duplex value. As a result, make sure that RMAN does not start more sessions than the maximum mount points allowed by the Tivoli Storage Manager server. The node definition option on the Tivoli Storage Manager server maxnummp determines the maximum number of mount points a client node can use on the Tivoli Storage Manager server during a backup operation. View the maximum mount points that are allowed by the Tivoli Storage Manager server for a particular node by entering the query node command from a Tivoli Storage Manager Administrative Client prompt: 
    q node f=d
    See the appropriate Tivoli Storage Manager Administrator's Reference for more information about this option.

Review your current Oracle documentation about the duplex backup function.