An Oracle Standalone Cluster hosts all Oracle Grid Infrastructure services and Oracle ASM locally and requires direct access to shared storage.
Oracle Standalone Clusters contain two types of nodes arranged in a hub and spoke architecture: Hub Nodes and Leaf Nodes. The number of Hub Nodes in an Oracle Standalone Cluster can be as many as 64. The number of Leaf Nodes can be many more. Hub Nodes and Leaf Nodes can host different types of applications. Oracle Standalone Cluster Hub Nodes are tightly connected, and have direct access to shared storage. Leaf Nodes do not require direct access to shared storage. Hub Nodes can run in an Oracle Standalone Cluster configuration without having any Leaf Nodes as cluster member nodes, but Leaf Nodes must be members of a cluster with a pool of Hub Nodes. Shared storage is locally mounted on each of the Hub Nodes, with an Oracle ASM instance available to all Hub Nodes.
Oracle Standalone Clusters host Grid Infrastructure Management Repository (GIMR) locally. The GIMR is a multitenant database, which stores information about the cluster. This information includes the real time performance data the Cluster Health Monitor collects, and includes metadata required for Rapid Home Provisioning.
When you deploy an Oracle Standalone Cluster, you can also choose to configure it as an Oracle Extended cluster. An Oracle Extended Cluster consists of nodes that are located in multiple locations or sites.