In this configuration, a single cluster shares access to a storage device, typically over a SAN. You can only start an application on a node with access to the required storage. For example, in a multi-node cluster, any node that is designated to run a specific database instance must have access to the storage where the database's tablespaces, redo logs, and control files are stored. Such a shared disk architecture is also the easiest to implement and maintain. When a node or application fails, all data that is required to restart the application on another node is stored on the shared disk.

Figure: Shared disk architecture for basic cluster shows a shared disk architecture for a basic cluster.