Ensure that all prerequisites are complete prior to using
the Add Resource Group wizard to create a new
resource group to make resources available to a cluster.
Once resources are ready for use by PowerHA™ SystemMirror, you can assign related
resources to resource groups for easier management as single entities.
For example, if an application depends on one or more volume groups
and service IP addresses, you can place these resources in a single
resource group and manage them as one unit.
The following general rules and restrictions apply to resources
and resource groups:
- You add a resource group to a cluster, therefore at least one
cluster must be configured before you can configure and add a resource
group.
- Cluster resources must be part of a resource group in order for PowerHA SystemMirror to keep
the resources highly available. If you want a resource to be kept
separate, define a group for that resource alone. A resource group
can have one or more resources defined.
- A resource can be included in only one resource group.
- Components of a resource group must be unique. Put the application,
along with the resources it requires, in the same resource group.
- The service IP labels, volume group names and resource group names
must be both unique within the cluster and distinct from each other.
It is recommended that the name of a resource relate to the application
that uses it, as well as to any corresponding device. For example,
for a service IP label to be used by application X, you might you
a name such as appX_service_address.
- If a node participates in more than one resource group, make sure
that the node has the memory, network interfaces, and so forth necessary
to manage all resource groups simultaneously.