Previous to MySQL 5.1.6, asynchronous replication, more usually referred to simply as “replication”, was not available when using MySQL Cluster. MySQL 5.1.6 introduces master-slave replication of this type for MySQL Cluster databases. This section explains how to set up and manage a configuration wherein one group of computers operating as a MySQL Cluster replicates to a second computer or group of computers. We assume some familiarity on the part of the reader with standard MySQL replication as discussed elsewhere in this Manual. (See Chapter 16, Replication).

Normal (non-clustered) replication involves a “master” server and a “slave” server, the master being the source of the operations and data to be replicated and the slave being the recipient of these. In MySQL Cluster, replication is conceptually very similar but can be more complex in practice, as it may be extended to cover a number of different configurations including replicating between two complete clusters. Although a MySQL Cluster itself depends on the NDBCLUSTER storage engine for clustering functionality, it is not necessary to use the Cluster storage engine on the slave. However, for maximum availability, it is possible to replicate from one MySQL Cluster to another, and it is this type of configuration that we discuss, as shown in the following figure:

In this scenario, the replication process is one in which successive states of a master cluster are logged and saved to a slave cluster. This process is accomplished by a special thread known as the NDB binlog injector thread, which runs on each MySQL server and produces a binary log (binlog). This thread ensures that all changes in the cluster producing the binary log — and not just those changes that are effected via the MySQL Server — are inserted into the binary log with the correct serialization order. We refer to the MySQL replication master and replication slave servers as replication servers or replication nodes, and the data flow or line of communication between them as a replication channel.

For information about performing point-in-time recovery with MySQL Cluster and MySQL Cluster Replication, see Section 17.6.9.2, “Point-In-Time Recovery Using MySQL Cluster Replication”.