After understanding What is OracleAS cluster. There are two types of clusters:
- clusters managed using a file-based or database repository
- clusters managed manually by the administrator
The first type contains a collection of application server instances. Each instance has identical application deployments. Any configuration changes are replicated across all application server instances in a cluster. This results in homogeneity between instances that are part of a cluster.
In the case of OracleAS clusters managed using file-based repositories, the cluster-wide configuration is stored on the file system of an OracleAS instance otherwise known as the repository host. In the case of clusters managed using database repositories, the cluster-wide configuration is stored on the OracleAS Metadata Repository. These storage methods enable the cluster to function as a single instance. The benefits of scalability, manageability, and availability are characteristic of repository managed clusters.
This is not the case with the second cluster type. Here the administrator needs to separately manage the configuration of each cluster instance. This means that while this type provides the benefits of scalability and availability, it does not offer easy manageability.