let me detail one of the many questions which come in from time to time.
Many times I have been asked to provide an explanation because:
"Cluster Enabler failed over the cluster groups"
Lets start with a statement: Cluster Enabler will not make any decisions (one exception to this), and will not cause the cluster groups to failover (one exception to this), nor will it actually actively failover any cluster groups.
Besides the exceptions noted, which I will come back to further down. Cluster Enabler is merely a resource in the cluster, and will follow the groups and cluster where they want to "go".
Microsoft Windows Server Failover Cluster is in control, all the normal rules for cluster failover are honoured, and cluster will determine the failover based on the set error detecting properties of cluster itself.
Cluster still behaves as if it was a normal cluster, it will perform error detecting, and the following three methods are used:
Based on the error detection routines within cluster, it is cluster to determines:
As cluster is a highly customisable engine itself, there are many factors which influences the failover decision of cluster. Here are the most common ones:
All this is done, the error detecting, the decision to failover (or not), and where to move to, by cluster.
Cluster Enabler does not come into play in this logic, it is merely a resource in the cluster.
Hope this clears up the situation of "Cluster Enabler failed over the group", the answer for that is: Cluster detected an error, and Cluster failed over the group. That will give you a good start when looking at those situations.
I mentioned 2 exceptions:
And there you have it, failover of cluster in a multi-site cluster using Cluster Enabler.
It is basically and not much more than any other cluster !
All the normal cluster logic applies
Please let me know if you have any questions