Preparing for the fast replication backup

Because the task of establishing a valid DFSMShsm fast replication environment can be nontrivial, DFSMShsm provides a PREPARE keyword that you can use with the FRBACKUP command. The PREPARE keyword allows you to validate your fast replication environment for DFSMShsm. DFSMShsm preassigns the required number of target volumes to each source volume in each storage group in the specified copy pool.

When you specify the PREPARE keyword, DFSMShsm verifies that there are sufficient eligible target volumes in the specified copy pool backup storage group. The PREPARE function does not create a backup of the copy pool, but only does initial processing. If VERSIONS=0 is defined for the copy pool, DASD backup volumes are not preassigned to the copy pool source volumes, but PREPARE does check that sufficient target volumes are available. You should only define VERSIONS=0 for a copy pool without fast reverse restore capability when only a tape backup copy is desired. With VERSIONS=0 and Allow Fast Reverse Restore=N specified, you cannot recover from the DASD backup copy.

Example: If you specified in the copy pool definition that DFSMShsm should keep two backup versions (VERSIONS=2), DFSMShsm preassigns two target volumes to each source volume in the copy pool.

The PREPARE function supports volume preferencing. DFSMShsm prefers an eligible copy pool backup storage group volume in the same cluster as the source volume. If such a volume is unavailable, DFSMShsm selects any fast replication eligible volume.

Use the PREPARE keyword whenever there is a change in the fast replication environment. Changing any of the following definitions will change the fast replication environment:

The volumes in the pool or copy pool backup storage group are changed or removed.
The number of backup versions for DFSMShsm to maintain is changed.
The storage groups defined to the copy pool have changed.

You can use the PREPARE keyword on the FRBACKUP command to verify whether a Metro Mirror primary volume is allowed to become a target of a FlashCopy® operation. For more information about the SMS copy pool settings for allowing Metro Mirror primary volumes to be used during fast replication backup, see Using Metro Mirror primary volume during fast replication backup.

Note:

If you specify the PREPARE keyword, DFSMShsm does not save the catalog information.
If the PREPARE function fails, make the necessary corrections and reissue the PREPARE function until it is successful.