Your network consists of a single Active Directory domain. The network contains a file server that
runs Windows Server 2008 R2. All servers use internal storage only. You plan to deploy a
client/server Application. You need to deploy the Application so that it is available if a single server
fails. You must achieve this goal while minimizing costs. What should you do?
A.
Deploy RemoteApp.
B.
Deploy a failover cluster that uses No Majority: Disk Only.
C.
Deploy a failover cluster that uses Node and File Share Disk Majority.
D.
Deploy Distributed File System (DFS) and configure replication.
Explanation:
Understanding Cluster Quorum Models
Quorums are used to determine the number of failures that can be tolerated within a cluster before
the cluster itself has to stop running. This is done to protect data integrity and prevent problems that
could occur because of failed or failing communication between nodes.
Quorums describe the configuration of the cluster and contain information about the cluster
components such as network adapters, storage, and the servers themselves. The quorum exists as a
database in the registry and is maintained on the witness disk or witness share. The witness disk orshare keeps a copy of this configuration data so that servers can join the cluster at any time,
obtaining a copy of this data to become part of the cluster.
One server manages the quorum resource data at any given time, but all participating servers also
have a copy.
You can use the following four quorum models with Windows Server 2008 Failover Clusters:
■Node Majority Microsoft recommends using this quorum model in Failover Cluster deployments
that contain an odd number of cluster nodes. A cluster that uses the Node Majority quorum model is
called a Node Majority cluster and remains up and running if the number of available nodes exceeds
the number of failed nodes—that is, half plus one of its nodes is available. For example, for a sevennode cluster to remain online, four nodes must be available. If four nodes fail in a seven-node Node
Majority cluster, the entire cluster shuts down. You should use Node Majority clusters in
geographically or network-dispersed cluster nodes. To operate successfully this model requires an
extremely reliable network, high-quality hardware, and a third-party mechanism to replicate backend data.
■Node and Disk Majority Microsoft recommends using this quorum model in clusters that contain
even numbers of cluster nodes. Provided that the witness disk remains available, a Node and Disk
Majority cluster remains up and running when one-half or more of its nodes are available. A six-node
cluster will not shut down if three or more nodes plus its witness disk are available. In this model,
the cluster quorum is stored on a cluster disk that is accessible to all cluster nodes through a shared
storage device using Serial Attached SCSI (SAS), Fibre Channel, or iSCSI connections. The model
consists of two or more server nodes connected to a shared storage device and a single copy of the
quorum data is maintained on the witness disk. You should use the Node and Disk Majority quorum
model in Failover Clusters with shared storage, all connected on the same network and with an even
number of nodes. In the case of a witness disk failure, a majority of the nodes need to remain up and
running. For example, a six-node cluster will run if (at a minimum) three nodes and the witness disk
are available. If the witness disk is offline, the same six-node cluster requires that four nodes are
available.
Exam Tip If the 70-646 examination asks which quorum model is the closest to the traditional singlequorum device cluster configuration model, the answer is the Node and Disk Majority quorum
model.
■Node and File Share Majority This configuration is similar to the Node and Disk Majority model, but
the quorum is stored on a network share rather than on a witness disk. A Node and File Share
Majority cluster can be deployed in a similar fashion to a Node Majority cluster, but as long as the
witness file share is available the cluster can tolerate the failure of half its nodes. You should use the
Node and File Share Majority quorum model in clusters with an even number of nodes that do not
utilize shared storage.
■No Majority: Disk Only Microsoft recommends that you do not use this model in a production
environment because the disk containing the quorum is a single point of failure. No Majority: Disk
Only clusters are best suited for testing the deployment of built-in or custom services and
applications on a Windows Server 2008 Failover Cluster. In this model, provided that the disk
containing the quorum remains available, the cluster can sustain the failover of all nodes except one.
MORE INFO Quorum models webcast
Four quorum models are available with Windows Server 2008. For more information on the models,
view the TechNet webcast at http ://msevents.microsoft.com/CUI/WebCastEventDetails .aspx?
EventID=1032364841&EventCategory=4&culture=en-US&CountryCode=US