M7 - Lesson 4: High availability with failover clustering in Windows…
M7 - Lesson 4: High availability with failover clustering in Windows Server 2016
Clustering categories & types
Nodes or witness server hosted in Azure
Single site cluster
Types of application deployed
is deployed for stateless applications, such as web servers. Stateless applications do not have long-running in-memory states and work with data that is read-only or that does not change frequently. Stateless applications treat each client request as an independent operation, and they can load-balance each request independently. Stateless applications include web servers, VPNs, FTP servers, and firewall and proxy servers.
are deployed for stateful applications, such as SQL Server and Exchange Server. Stateful applications have long-running in-memory states, or have large, frequently updated data states. Other types of failover cluster applications include Hyper-V, file servers, and print servers.
Computers that connect to the failover cluster and are not aware which node the service is running on.
: The process of moving cluster resources from the first node to the second node, as a result of node failure or administrator’s action.
: A server that is participating in cluster voting when the number of nodes is even.
: A Windows Server 2016 computer that is part of a failover cluster, and has the failover clustering feature installed.
: The process of moving cluster resources back from the second node to the first node, as a result of the first node going online again or an administrator’s action. If the service or application fails over from Node1 to Node2, when Node1 is again available, the service or application will fail back to Node1.
Service or Application
: A service that can be moved between cluster nodes (for example, a clustered file server can run on either node).
: The number of elements that must be online for a cluster to continue to run. The quorum is determined when cluster nodes vote.
: External storage that is accessible to all cluster nodes.
High availability with failover clustering
Applications must be cluster-aware (DFS, DHCP, DTC, File Server, iSNS, Print Server, WINS server)
Applications have specific failover clustering configurations
Failover clustering provides high availability for data, applications and services.
Cluster node properties
Is aware of the services or applications that are running locally, and the resources that are running on all other cluster nodes.
Is connected through a shared bus or iSCSI connection to shared storage.
Is connected to a network through which client computers can access the cluster.
Is aware when another node joins or leaves the cluster.
Has full connectivity and communication with the other nodes in the cluster.
What is Failover Clustering
A failover cluster is a group of independent computers that work together to increase the availability of applications and services. Physical cables and software connect the clustered servers, known as nodes.
A cluster is a group of computers and storage devices that work together as a single organized system.