For each hub in the replicated topology:
Disable replication agreements from the masters to the hub you want to migrate.
Disable replication agreements from the hub you want to migrate to the consumers.
Stop the hub.
Migrate the hub according to the instructions under Chapter 2, Overview of the Migration Process for Directory Server.
Start the hub.
Enable the replication agreements from the masters to that hub.
Enable the replication agreements from that hub to the consumers.
If you have migrated the data, check that replication is in sync.
If you have not migrated the data, reinitialize the hub.
The following sequence of diagrams illustrate the migration of a hub, as described above. The first diagram shows the topology before migrating the hubs.
The first migration step involves disabling replication agreements, effectively isolating the hub from the topology.
The next step involves migrating the legacy hub.
The next step involves enabling the replication agreements to the new hub and initializing the hub if necessary.
Check that the replication on the consumers is in sync with the rest of the topology before migrating another hub. A server that has just been migrated does not have a change log, and can therefore not update consumer servers that are out of sync. Allow the topology to stabilize and all servers to synchronize before migrating the next supplier server.