Why Configure a Service Group Dependency?

While defining a cluster configuration, typically a service group and an application have a one-to-one relationship. For example, a service group hosts an application, or an application is contained within a service group. In a distributed computing environment there may be multiple applications running within a cluster, and one application may depend on another. For example, a database server may have several database applications depending on its services. In such situations, it is imperative that a dependency rule be specified for how groups are brought online and taken offline.

For example, you can define a rule that requires a database server (a child group) to be online before any or all database applications (parent group) can be brought online. You can also define a rule that requires database applications to fail over when the database server faults.