Replica. This is a copy of a cluster partition. Each node in a node group Stores a replica. Also
sometimes known as a parłitbn replica. The number of replicas is equal to the number of nodes per node group.
The following diagram illustrates a MySQL Cluster with four data nodes, arranged in twD node groups
of two nodes each; nodes 1 and 2 belong to node group 0, and nodes 3 and 4 belong to node group
1. Notę that only data (ndbd) nodes are shown here; although a working cluster requires an ndb_mgm
process for cluster management and at least one SQL node to access the data stored by the cluster,
these have been omitted in the figurę for clarity.