Step 3: Define Node Topologies

Node topologies restrict data to a designated set of nodes. When you define a topology, data is only replicated on the nodes within the topology. Node topologies improve query performance because data is localized to the nodes specified in the topology instead of being distributed across the entire MapR cluster.

You can create node topologies for the Drill clusters in the MapR Control System or from the CLI. See Changing Topology for One or More Nodes for instrcutions.

When you create a topology, you define the nodes that form a Drill cluster, as shown in the following image:

The image above shows a topology named T1 for the Drill cluster that will ultimately become the OJAI Distributed Query Service cluster and T2 for the Drill cluster that will remain a Drill service cluster.