Red Hat DIRECTORY SERVER 8.0, Руководство администратора

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Chapter 8. Managing Replication
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• In the case of cascading replication, the hub server holds a read-only replica that it supplies to
consumers.
Section 8.2.3, “Cascading Replication”
has more information.
• In the case of multi-master replication, the
masters
are both suppliers and consumers for the same
information. For more information, see
Section 8.2.2, “Multi-Master Replication”
.
Replication is always initiated by the supplier server, never by the consumer (
supplier-initiated
replication
). Supplier-initiated replication allows a supplier server to be configured to push data to
multiple consumer servers.
8.1.4. Changelog
Every supplier server maintains a
changelog
, a record of all changes that a supplier or hub needs to
send to its consumers. A changelog is a special kind of database that describes the modifications that
have occurred on a replica. The supplier server then replays these modifications to the replicas stored
on consumer servers or to 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.
In Directory Server, the changelog is only intended for internal use by the server. For other
applications to read the changelog, use the Retro Changelog Plug-in, as described in
Section 8.16,
“Using the Retro Changelog Plug-in”
.
8.1.5. Replication Identity
When replication occurs between two servers, the replication process uses a special entry, called
the
replication manager
entry, to identify replication protocol exchanges and to control access to the
directory data. The replication manager entry, or any entry used during replication, must meet the
following criteria:
• It is created on the consumer server (or hub) and
not
on the supplier server.
• Create this entry on
every
server that receives updates from another server, meaning on every hub
or dedicated consumer.
• When a replica is configured as a consumer or hub (a replica which receives updates from another
server), this entry must be specified as the one authorized to perform replication updates.
• The replication agreement is created on the supplier server, the DN of this entry must be specified in
the replication agreement.
• The supplier bind DN entry must not be part of the replicated database for security reasons.
• This entry, with its special user profile, bypasses all access control rules defined on the consumer
server for the database involved in that replication agreement.
NOTE
In the Directory Server Console, this replication manager entry is referred to as the
supplier bind DN
, which may be misleading because the entry does not actually exist