Sun Microsystems 8190994 manual Migration Scenarios, Migrating the Consumers

Migration Scenarios

Advantages of an all-master topology include the following:

■Availability. Write traffic is never disrupted if one of the servers goes down.

■Simplicity. In an all-master topology, there is no need to set up referrals to route reads and writes to different servers.

There may be reasons that an all-master topology is not viable in a specific deployment. For example, fractional replication cannot be used in an all-master topology because fractional replication is only supported from masters to consumers.

Migration Scenarios

This section provides sample migration scenarios for a variety of replicated topologies.

Migrating a Replicated Topology to an Identical

Topology

Before you start migrating replicated servers, determine whether your deployment might not be better served by changing the architecture of the topology. This section describes how to migrate if you want to keep your existing topology. Migrating a replicated topology to an identical topology, involves migrating the consumers, then the hubs, then the masters. The following sections demonstrate a sample migration of a simple multi-master topology.

Migrating the Consumers

For each consumer in the replicated topology:

1.Reroute clients to another consumer in the topology.

2.Disable any replication agreements to the consumer you want to migrate.

3.Stop the consumer.

4.Migrate the consumer according to the instructions under Chapter 1.

5.Start the consumer.

6.Enable the replication agreements from the hubs to that consumer.

7.If you have migrated the data, check that replication is in sync.

8.If you have not migrated the data, reinitialize the consumer.

9.Reroute clients back to the consumer.

The following sequence of diagrams illustrate the migration of a consumer, as described above. The first diagram shows the version 5 topology before the migration.

54 Sun Java System Directory Server Enterprise Edition 6.0 Migration Guide • March 2007

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