File Share Witness
The file share witness feature is an improvement to the current Majority Node Set (MNS) quorum model. This feature lets you use a file share that is external to the cluster as an additional “vote” to determine the status of the cluster in a two-node MNS quorum cluster deployment.
Consider a two-node MNS quorum cluster. Because a MNS quorum cluster can only run the majority of the cluster nodes that are available, a two-node MNS quorum cluster is unable to sustain the failure of any cluster node. This is because the majority of a two-node cluster is two. To sustain the failure of any one node in an MNS quorum cluster, you must have at least three devices that can be considered as available. The file share witness feature enables you to use an external file share as a witness. This witness acts as the third available device in a two-node MNS quorum cluster. Therefore, with this feature enabled, a two-node MNS quorum cluster can sustain the failure of a single cluster node.
Configurable Cluster Heartbeats
The configurable cluster heartbeats feature enables you to configure cluster heartbeat parameters. This may help you avoid unnecessary cluster failovers. These failovers occur because of a temporary network problem that may cause packets to be dropped or delayed. The configurable cluster heartbeats feature may help in an environment where cluster nodes are geographically dispersed.
For details, please refer to the KB article listed below:
An update is available that adds a file share witness feature and a configurable cluster heartbeats feature to Windows Server 2003 Service Pack 1-based server clusters