Suppliers and Consumers

A Directory Server that replicates to other servers is called a supplier. A Directory Server that is updated by other servers is called a consumer. The supplier replays all updates on the consumer through specially designed LDAP v3 extended operations. In terms of performance, a supplier is therefore likely to be a demanding client application for the consumer.

A server can be both a supplier and a consumer, as in the following situations:

• In multi-master replication, a master replica is mastered on two different Directory Servers. Each server acts as a supplier and a consumer of the other server.

• When the server contains a hub replica, the server receives updates from a supplier and replicates the changes to consumers.

A server that plays the role of a consumer only is called a dedicated consumer.

For a master replica, the server must do the following:

• Respond to update requests from directory clients

• Maintain historical information and a change log

• Initiate replication to consumers

The server that contains the master replica is responsible for recording any changes made to the master replica and for replicating these changes to consumers.

For a hub replica, the server must do the following:

• Respond to read requests

• Refer update requests to the servers that contain a master replica

• Maintain historical information and a change log

• Initiate replication to consumers

For a consumer replica, the server must do the following:

• Respond to read requests

• Maintain historical information

• Refer update requests to the servers that contain a master replica