Resources and resource groups
A resource is any cluster element such a cluster node, database, mount point, or network interface card that has been registered with a cluster manager. If an element is not registered with the cluster manager, then the cluster manager will not be aware of that element and the cluster manager will not include that element in cluster managing operations. A resource group is a logical collection of resources. The resource group is a very powerful construct because relationships and constraints can be defined on resource groups that simplify performing complex administration tasks on the resources in those groups.
When a cluster manager collects resources into groups,
the cluster manager can operate on all those resources collectively.
For example, if two databases called database-1 and database-2 belong
to the resource group called resource-group-A, then
if the cluster manager performs a start operation on resource-group-A then
both database-1 and database-2 would
be started by that one cluster manager operation.
Restrictions
- A resource group cannot contain an equivalency and an equivalency cannot contain a resource group (An equivalency is a set of resources that provide the same functionality as each other and can fail over for each other.)
- A resource can only be in one resource group
- A resource cannot be in a resource group and in an equivalency
- A resource group can contain other resource groups, but the maximum nesting level is 50
- The maximum number or resources that you can collect in a resource group is 100