Units 8 and 9 Server Administration
Shared Virtual Hard Disk
A virtual hard disk configured on a VM in a guest cluster that's used for shared storage among VMs in the guest cluster instead of traditional SAN storage.
Hyper-Converged Storage Spaces Direct Deployment
A server cluster configuration that incorporates both the storage and the Hyper-V role within the same cluster.
Disaggregated Storage Spaces Direct Deployment
A server cluster configuration with two separate clusters: an S2D cluster and a Hyper-V cluster.
Port Rule
A setting that specifies which type of TCP or UDP traffic that an NLB cluster should respond to and how the traffic is distributed among cluster members. See also network load balancing (NLB).
Heartbeat
A signal sent between cluster nodes informing them that a node is up and running.
Cluster Shared Volume
A storage option in a failover cluster in which all cluster nodes have access to the shared storage for read and write access. See also failover cluster.
Core Cluster Resource
Resources in a failover cluster that include the quorum resource, which is usually the witness disk or witness share; the IP address resource that provides the cluster IP address; and the network name resource that provides the cluster name.
Scale-Out File Server (SoFS)
A highly available share option that provides the reliability of failover clusters and the load distribution of an NLB because client connections are distributed among all nodes in the cluster.
Shared-Nothing Live Migration
A live migration done between Hyper-V servers that have no common storage.
Hot Backup Site
A location that duplicates much of the main site's IT infrastructure and can be switched to if a disaster occurs at the main site.
Failover Affinity
A method that allows failover to occur to a node in the same site before failing over to a node in a different site.
Quick Migration
A migration option available only between Hyper-V servers in a failover cluster; usually results in a minute or more of downtime, depending on how much memory the VM uses.
Client Access Point
A name and IP address by which clients can access a clustered service in a failover cluster. See also failover cluster.
High Availability
A network or computer configuration in which data and applications are almost always available, even after a system failure.
VHD Set
A new VHD option in Windows Server 2016 designed specifically for shared virtual hard disks that enables backup of virtual machine groups and online disk resizing, and supports Hyper-V Replica.
Node Fairness
A new failover cluster feature in Windows Server 2016 that helps optimize usage of failover cluster node members.
Site-Aware Cluster
A new feature in Windows Server 2016 that allows an administrator to assign a name to a physical location (site) and assign cluster nodes to each location.
Storage Spaces Direct (S2D)
A new feature in Windows Server 2016 that extends the storage pool concept on a single server to multiple servers in a failover cluster.
Cloud Witness
A new quorum witness option introduced in Windows Server 2016 that allows you to specify a resource in Microsoft Azure to act as the cluster witness.
Fault Domain
A property of a cluster that has name, type, description, and location values.
Dynamic Witness
A quorum feature in Windows Server 2012 R2 in which the cluster determines whether to give the witness a quorum vote based on whether there's an odd or even number of cluster nodes.
Split Vote
A quorum situation in which no quorum can be reached.
Virtual Machine Monitoring
A feature introduced in Windows Server 2012 that allows monitoring resources, applications, and services running on highly available VMs. See also highly available virtual machine.
Dynamic Quorum
A feature that assigns a cluster node vote dynamically depending on whether the node is an active member of the cluster. If a node is no longer active in the cluster, its vote is removed.
Storage Migration
A VM migration process used to move a VM's storage from one volume to another without moving the VM to another Hyper-V server.
Cluster Operating System Rolling Upgrade
A Windows Server 2016 OS upgrade option that can upgrade a Windows Server 2012 R2 cluster to a Windows Server 2016 cluster without taking the workloads offline
Network Load Balancing (NLB)
A Windows Server feature that uses server clusters to provide scalability and fault tolerance. See also server cluster.
Cluster Server
A Windows server that participates in a failover cluster; also referred to as a cluster node or cluster member. See also failover cluster.
Recovery Point
A checkpoint that can be generated automatically so that you can revert to an earlier server state if there's an unplanned failover and the VM is in an unworkable state.
Active Directory-Detached Cluster
A cluster configuration option that allows deploying a failover cluster without needing Active Directory for network name management.
Passive Node
A cluster member that's not currently responding to client requests for a clustered application but is in standby in case the active node fails; also called a passive server.
Active Mode
A cluster member that's responding to client requests for a network application or service; also referred to as an active server.
Standby Mode
A cluster node that isn't active.
Cluster Operation Mode
A cluster parameter that specifies the type of network addressing used to access the cluster: Unicast, Multicast, or IGMP multicast.
Partitioned
A cluster status that can occur if communication fails between cluster servers, resulting in two or more subclusters, each with the objective of handling the clustered service. See also cluster server.
Guest Clustering
A clustering feature that requires two or more VMs with a guest OS installed and configured for failover clustering; the failover clustering occurs in the VM's guest OS.
Quorum
A database containing cluster configuration information about the status of each node (active or passive) for clustered applications. In a server or communication failure, it's also used to determine whether the cluster is to remain online and which servers should continue to participate in the cluster.
Cluster-Aware Updating
A failover cluster feature in Windows Server that automates software updates on cluster servers while maintaining cluster service availability. See also failover cluster.
Virtual Machine Network Health Protection
A failover cluster feature that automatically livemigrates a virtual machine to another node if its network connection fails.
Tie Breaker For 50% Node Split
A feature in Windows Server 2012 R2 in which a cluster is partitioned into an equal numbers of nodes, and the dynamic quorum feature is used to change node votes to break the tie. See also dynamic quorum.
Hyper-V Replica
A feature in Windows Server 2016 that periodically replicates changes in a VM to a mirror VM hosted on another Hyper-V server
Drain On Shutdown
A feature in Windows Server 2016 that drains roles automatically and live-migrates VMs to another cluster node before the Hyper-V server shuts down.
Server Cluster
A group of two or more servers configured to respond to a single virtual IP address.
High Available Virtual Machine
A virtual machine (VM) that allows you to make applications and services highly available by installing them on a VM residing on a Hyper-V server configured for high availability.
Rolling Upgrade
An NLB cluster upgrade method that involves taking each cluster node offline, upgrading the host, and then bringing it back online. See also network load balancing (NLB).
Load Weight
An NLB parameter that allows configuring how much network traffic, as a percentage, each node should handle. See also network load balancing (NLB).
Handling Priority
An NLB parameter used in single host mode that determines which host handles all traffic meeting the port rules' criteria. See also filtering mode and network load balancing (NLB).
Clustered Application
An application or service installed on two or more servers participating in a failover cluster; Also called a clustered service. See also failover cluster.
Live Migration
An application or service installed on two or more servers participating in a failover cluster; also called a clustered service.
Filtering Mode
An option in a port rule that specifies whether multiple hosts or a single host responds to traffic identified by the port rule. Multiple host is the default mode and allows scalability. Single host mode specifies that the server with the highest priority value handles traffic.
Client Affinity Value
An option specified in multiple host filtering modes that determines whether the same or a different host handles successive requests from the same client.
Cluster Heartbeat
Communication between cluster nodes that provides the status of each cluster member to the cluster quorum. The cluster heartbeat, or lack of it, informs the cluster when a server is no longer communicating.
Replica Server
In the Hyper-V Replica feature, the Hyper-V server where replication is enabled.
Failover Options
Settings that specify how many times a service attempts to restart or fail over to another server in the specified period.
Failback Options
Settings that specify that a cluster should revert to the most preferred owner when that server is available again. The failback can occur immediately or between certain hours of the day.
Witness Disk
Shared storage used to store cluster configuration data and help determine the cluster quorum.
Virtual IP Address
The IP address by which networking services provided by an NLB cluster are accessed by network clients. A DNS host record should exist for the cluster name mapped to this address. See also network load balancing (NLB).
Preferred Owner
The server selected as the active server for a service or an application.
Failover Cluster
Two or more servers appearing as a single server to clients. One server is considered the active server, and other servers are passive. The active server handles all client requests for the clustered application, and the passive servers wait in standby mode until the active server fails.
