When one instance departs the cluster, the GRD portion of that instance needs to be redistributed to the surviving nodes. Similarly, when a new instance enters the cluster, the GRD portions of the existing instances must be redistributed to create the GRD portion of the new instance.
Instead of remastering all resources across all nodes, RAC uses an algorithm called lazy remastering to remaster only a minimal number of resources during reconfiguration. This is illustrated in the slide. For each instance, a subset of the GRD being mastered is shown along with the names of the instances to which the resources are currently granted. When the second instance fails, its resources are remastered on the surviving instances. As the resources are remastered, they are cleared of any reference to the failed instance.
Instead of remastering all resources across all nodes, RAC uses an algorithm called lazy remastering to remaster only a minimal number of resources during reconfiguration. This is illustrated in the slide. For each instance, a subset of the GRD being mastered is shown along with the names of the instances to which the resources are currently granted. When the second instance fails, its resources are remastered on the surviving instances. As the resources are remastered, they are cleared of any reference to the failed instance.
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