Q: How do the automatic metrics work with Windows Server 2012 R2 clusters?

A: Clustering generates an automatic metric for each cluster network, which is used to determine the prioritization of the network to be used for cluster communications.

The lower the metric value the "cheaper" it is and therefore more better to use. The lowest metric is used for cluster communications.

The metrics are generated as follows:

  • An initial metric value is given as starting value: 40000 for a network only to be used for clustering, 80000 for a network that is used for clustering and public communications.
  • If the NIC supports Remote Direct Memory Access (RDMA), then around 19200 is removed.
  • If the NIC supports Receive-Side Scaling (RSS), then around 9600 is removed.
  • Then the speed of the NIC, if it's over 1GB, is removed, along with consideration of whether it's teamed.