Failover clusters provide high availability and scalability to many server workloads. These include server applications such as Microsoft Exchange Server, Hyper-V, Microsoft SQL Server, and file servers. The server applications can run on physical servers or virtual machines. In a failover cluster, if one or more of the clustered servers (nodes) fails, other nodes begin to provide service. This process is known as failover.
What’s New in Failover Clustering in Windows Server 2012 & 2012R2 – Click to open PDF
Understanding Quorum in Windows Server Failover Cluster(WSFC)
Quorum acts as a definitive repository for the configuration information of physical clusters and in simple it can be called as cluster configuration database. When network problems occur, they can interfere with communication between cluster nodes.
Although the quorum is just a configuration database, it has two very important jobs. Firstly, it tells the cluster which node should be active and the other thing that the quorum does is to intervene when communications fail between nodes.
Understanding Failover Cluster Networks
Windows Server 2012 supports the concept of converged networking, where different types of network traffic share the same Ethernet network infrastructure. In previous versions of Windows Server, the typical recommendation for a failover cluster was to dedicate separate physical network adapters to different traffic types
Overview of different network traffic types
When you deploy a Hyper-V cluster, you must plan for several types of network traffic. The following table summarizes the different traffic types.
Understanding Cluster Shared Volumes(CSV)
Cluster Shared Volumes (CSV) enable multiple nodes in a failover cluster to simultaneously have read-write access to the same LUN (disk) that is provisioned as an NTFS volume. With CSV, clustered roles can fail over quickly from one node to another node without requiring a change in drive ownership, or dismounting and remounting a volume. CSV also help simplify the management of a potentially large number of LUNs in a failover cluster.
A single CSV can handle hundreds of virtual machines (VMs) and applications—there is no need for a separate logical unit number (LUN) for each VM or application. Each instance of CSV has its own namespace—CSV does not need to use drive letters, making it a more scalable technology than mapped drives
CSV feature introduced firstly in Windows 2008 R2 and significantly enhanced in 2012 (CSV 1.0). Below are the key features in 2012