Monitored resources are types of system resources that can be managed by a cluster administrative domain. These resources are represented in the cluster administrative domain as monitored resource entries (MREs).
A monitored resource entry can be added to the cluster administrative domain for the following types of resources:
An MRE can only be added to the cluster administrative domain if all nodes in the domain are active and participating in the group. An MRE cannot be added if the cluster administrative domain is partitioned. Once the MRE is added, changes to the resource represented by the MRE are propagated to all active nodes in the domain when the peer CRG is started. If the CRG is ended, pending changes will be propagated to the active domain when the CRG is started again.
There is a global status associated with an MRE. When the resource represented by an MRE has the same values for all of the attributes that are being monitored on all nodes in the active domain, the global status for that resource is consistent. If the cluster administrative domain attempts to update a resource on one or more nodes, and the update fails, the global status of the resource is inconsistent. When the global status is inconsistent, the administrator must determine the cause of the failure and correct it. The cluster administrative domain will attempt to resynchronize the resource the next time it is updated, probably when the administrator changes the resource as a result of fixing the problem which caused an update to fail, or when the CRG is restarted.
When the cluster administrative domain CRG is ended, the global status for all MREs is set to inconsistent. This is because while the CRG is ended, changes can be made to monitored resources on different nodes and they therefore become inconsistent.
If the resource represented by an MRE is a system object, it should not be deleted, renamed or moved to a different library without removing the MRE first. If a resource is deleted, renamed or moved to a different library, the global status for the MRE will be inconsistent and any changes made to the resource on any node after that will not be propagated to the cluster administrative domain.
When a node is added to the cluster administrative domain, all of the MREs from the active domain will be copied to the new node. Any resources represented by an MRE which do not exist on the new node will be created and the values of the attributes will be set to the same values as the active cluster administrative.
If there are nodes in the cluster administrative that are not active, any resource changes that are made in the active domain will be propagated to the inactive nodes once they rejoin the active domain. If a cluster administrative domain is partitioned, changes will continue to be synchronized among the active nodes in each partition. When the nodes are merged back together again, the cluster administrative domain will propagate all changes made in every partition so that the resources are consistent within the active domain. If multiple changes were made in different partitions to the same resource, each change will be processed by the cluster administrative domain after the partitions are merged, although the sequence is indeterminate.
