About Cluster Topology
The cluster topology in Oracle Big Data Cloud is based on the initial size of the cluster when it was first created. While a cluster can be scaled up or down later, the underlying cluster topology that defines master services remains unchanged. Therefore, when you’re creating a cluster, it’s important to consider the maximum anticipated size of the cluster and start with a master topology that can scale to meet the expected demands.
Big Data Cloud provides three different cluster topologies based on the initial size of the cluster when it was created. These topologies are described in the following table.
| Initial Cluster Size | Description |
|---|---|
|
1 or 2 nodes |
A cluster initially created with 1 or 2 nodes has a single master node that hosts all master services. This topology is well suited for smaller clusters of less than 5 nodes. A cluster initially created with 1 or 2 nodes is not expected to scale well beyond several nodes. This type of cluster is not highly available. All services run on the same node in non-HA mode. This cluster has:
|
|
3 nodes |
A cluster initially created with 3 nodes has 3 master nodes that host all master services. These nodes also act as storage and compute nodes. This type of cluster is expected to scale to 10 nodes and is highly available. This cluster has:
|
|
4+ nodes |
A cluster initially created with 4 nodes has 4 master nodes, 2 of which provide NameNode services and 2 others that host the other master services. Larger clusters should initially be created with 4 nodes. This type of cluster is highly available. This cluster has:
|