Replication terminology

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This glossary defines technical terms that are used in this section.

Cascading replication
A replication topology in which there are multiple tiers of servers. A peer/master server replicates to a set of read-only (forwarding) servers, which in turn replicate to other servers. Such a topology offloads replication work from the master servers.
Consumer server
A server that receives changes through replication from another (supplier) server.
Credentials
Identify the method and required information that the supplier uses in binding to the consumer. For simple binds, the credentials include the DN and password. The credentials are stored in an entry the DN of which is specified in the replica agreement.
Note: This DN must be unique and cannot be same as any already existing DN's.
Forwarding server
A read-only server that replicates all changes sent to it. This term contrasts with a peer/master server in that it is read only and it can have no peers.
Gateway server
A server that forwards all replication traffic from the local replication site to other Gateway servers in the replicating network. Also receives replication traffic from other Gateway servers within the replication network, which it forwards to all servers on its local replication site.

Gateway servers must be masters (writable).

Master server
A server that is writable (can be updated) for a subtree.
Nested subtree
A subtree within a replicated subtree of the directory.
Peer server
The term that is used for a master server when there are multiple masters for a subtree. A peer server does not replicate changes that are sent to it from another peer server. It replicates only those changes that are originally made on it.
Replica group
The first entry that is created under a replication context has objectclass ibm-replicaGroup and represents a collection of servers that are participating in replication. It provides a convenient location to set ACL's to protect the replication topology information. The administration tools currently support one replica group under each replication context, named ibm-replicagroup=default.
Replica subentry
Below a replica group entry, one or more entries with objectclass ibm-replicaSubentry can be created; one for each server that is participating in replication as a supplier. The replica subentry identifies the role that the server plays in replication: master or read-only. A read-only server might, in turn, have replication agreements to support cascading replication.
Replicated subtree
A portion of the directory information tree (DIT) that is replicated from one server to another. Under this design, a subtree can be replicated to some servers, and not to others. A subtree can be writable on a server, while other subtrees can be read-only.
Replicating network
A network that contains connected replication sites.
Replication agreement
Information that is contained in the directory that defines the 'connection' or 'replication path' between two servers. One server is called the supplier (the one that sends the changes) and the other is the consumer (the one that receives the changes). The agreement contains all the information that is needed for making a connection from the supplier to the consumer and scheduling replication.
Replication context
Identifies the root of a replicated subtree. The ibm-replicationContext auxiliary object class can be added to an entry to mark it as the root of a replicated area. The configuration information that is related to replication is maintained in a set of entries that are created below the base of a replication context.
Replication site
A Gateway server and any master, peer, or replica servers that are configured to replicate together.
Schedule
Replication can be scheduled to occur at particular times, with changes on the supplier that is accumulated and sent in a batch. The replica agreement contains the DN for the entry that supplies the schedule.
Supplier server
A server that sends changes to another (consumer) server.
Replication topology
The set of objects in a directory that control the information is replicated between LDAP servers and how it is replicated, including:
  • Replication contexts
  • Replication groups
  • Replication subentries
  • Replication agreements
  • Replication credentials
  • Replication schedule entries
All LDAP servers in the replicating network must have the same replication topology.