What the migration utility does
After you have identified at least one classic zone as potential parent zones, you can use the migration utility to convert the classic zone into a hierarchical parent zone. After you make the classic zone a hierarchical zone, you can run the migration utility to make other classic zones into child zones of the parent zone.
During the migration, all of the user and group profiles in the source zone are copied to the specified parent zone. If identical profiles exist in multiple classic zones, the identical profiles become a single profile in the parent zone. If there are user or group profiles in multiple zones with different attribute values—for example, a UID of 10001 in one classic zone, but 10003 in another classic zone, the migration utility creates a single profile for the user in the parent zone, and creates a profile override with the distinct attribute values in each target child zone. Each child zone inherits the base profile from the parent zone but applies the overrides for any attributes that are different in different zones.
The migration utility copies everything else—including rights, roles, role assignments, groups, and NIS maps—into the new child zone for each classic zone being migrated.