Changelog; Replication Agreement - Red Hat DIRECTORY SERVER 7.1 - DEPLOYMENT Deployment Manual

Introduction to Replication
• Initiate replication to consumer servers.
The supplier server is always responsible for recording the changes made to the
read-write replicas that it manages, so the supplier server makes sure that any
changes are replicated to consumer servers.
A consumer server must:
• Respond to read requests.
• Refer update requests to a supplier server for the replica.
Any time a request to add, delete, or change an entry is received by a consumer
server, the request is referred to a supplier for the replica. The supplier server
performs the request, then replicates the change.
In the special case of cascading replication, the hub supplier must:
• Respond to read requests.
• Refer update requests to a supplier server for the replica.
• Initiate replication to consumer servers.
For more information on cascading replication, refer to "Cascading Replication,"
on page 121.

Changelog

Every supplier server maintains a changelog. A changelog is a record that
describes the modifications that have occurred on a replica. The supplier server
then replays these modifications on the replicas stored on consumer servers or on
other suppliers in the case of multi-master replication.
When an entry is modified, a change record describing the LDAP operation that
was performed is recorded in the changelog.

Replication Agreement

Directory Servers use replication agreements to define replication. A replication
agreement describes replication between one supplier and one consumer. The
agreement is configured on the supplier server. It identifies:
• The database to replicate.
• The consumer server to which the data is pushed.
• The times that replication can occur.
• The DN that the supplier server must use to bind (called the supplier bind DN).
114 Red Hat Directory Server Deployment Guide • May 2005