Creating a dependent resource is similar to the approach that we took in section 24.2 when creating a simple, highly available resource. The difference is that we must also create a resource (or resources) on which to depend.
Decide on the needs (or dependencies) of your application. If you have an application that connects to a database, for example, then you can define two application resources:
| – Create an application resource for the application that utilizes the database. Set the database application resource (DB) in either the OPTIONAL_RESOURCE or a REQUIRED_RESOURCE attribute list. |
| – Create an application resource for your database. |
Note, the resource names are made up and are not specific to any resource type.
Another example is an application resource that is used to backup a client system over the network. In this case the cluster acts as a backup server for other systems on the network. It stands to reason that the backup application should be located on a cluster member with a direct physical connection to the network as well as the backup media (tape and media robot). In this example, you can define four resources:
| – Create an application resource for your network backup program. Set the network (BackupNIC), tape (BackupTAPE), and changer (BackupROBOT) resources in either the OPTIONAL_RESOURCE or a REQUIRED_RESOURCE attribute list. |
| – Create a network resource. |
| – Create a tape resource. |
| – Create a changer resource. |
Note, as with the previous example the resource names are made up and are not specific to any resource type.
For additional information on dependent resources, see sections 23.6.1 and 23.6.2.