Primary and Secondary Migration

Each migration stage can contain a primary migration specification and, optionally, a secondary migration specification. Secondary migration produces a copy of primary migration reports (usually on less expensive media) that can be accessed if primary migration reports become damaged.

If SECONDARY MEDIA is specified in a migration mission, the migration mission submits the following migration jobs:

• The primary migration job uses the migration skeleton. For more information, see Migration Mission Skeleton Jobs whose name is identical to the migration mission name.
• The secondary migration job uses the migration skeleton whose name is specified in parameter SECONDARY SKELETON. This parameter defaults to the name of the primary migration mission, modified by changing the 3rd character to C (or to D if it had been C).

Only files designated as primary migration files can be accessed for viewing. If primary migration files are not usable for any reason, utility CTDUPBKP can be run to switch the primary and secondary migration designations. After running this utility, the secondary migration files are accessed for viewing. This utility can be run again to switch back to viewing primary migration files. The next Multi‑Stage Migration mission automatically recreates the primary migration files on the (originally) defined media.

Information about retention and about the current primary migration media can be displayed in $SYSDATA long format by using option A (Additional Info) in the Migrated Report list. Information about secondary migration media can be retrieved by running utility CTDUPBKP with parameter SIMULATE set to YES. For utility CTDUPBKP documentation, see the INCONTROL for z/OS Utilities Guide.

Secondary migration files are deleted when the next secondary migration is completed and at the end of the retention period. Refresh operations are performed independently for primary and secondary media.