A service group is a virtual container that contains all the hardware and software resources that are required to run the managed application. Service groups allow VCS to control all the hardware and software resources of the managed application as a single unit. When a failover occurs, resources do not fail over individually; the entire service group fails over. If more than one service group is on a system, a group can fail over without affecting the others.

Figure: Typical database service group shows a typical database service group.

A single node can host any number of service groups, each providing a discrete service to networked clients. If the server crashes, all service groups on that node must be failed over elsewhere.

Service groups can be dependent on each other. For example, a managed application might be a finance application that is dependent on a database application. Because the managed application consists of all components that are required to provide the service, service group dependencies create more complex managed applications. When you use service group dependencies, the managed application is the entire dependency tree.