This topic describes Failover Clustering functionality that is new or changed in Windows Server 2012. This functionality supports increased scalability, continuously available file-based server application storage, easier management, faster failover, and more flexible architectures for failover clusters.
Feature description
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. 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 (a process known as failover). In addition, the clustered roles—formerly called clustered services and applications—are proactively monitored to verify that they are working properly. If they are not working, they are restarted or moved to another node. In addition, failover clusters provide Cluster Shared Volume (CSV) functionality that provides a consistent, distributed namespace that clustered roles can use to access shared storage from all nodes in the cluster. For an overview of the Failover Clustering feature in Windows Server 2012, see Failover Clustering Overview.
New and changed functionality
The following table and sections summarize key Failover Clustering functionality in Windows Server 2012 that is new or changed since Windows Server 2008 R2.
| Feature/functionality | Windows Server 2008 R2 | Windows Server 2012 |
|---|---|---|
| Maximum cluster size |
|
|
| Management of large-scale clusters by using Server Manager and Failover Cluster Manager | X | |
| Management and mobility of clustered virtual machines and other clustered roles | X | |
| Cluster Shared Volumes | X | X |
| Support for Scale-Out File Servers | X | |
| Cluster-Aware Updating | X | |
| Virtual machine application monitoring and management | X | |
| Cluster validation tests | X | X |
| Active Directory Domain Services integration | X | X |
| Quorum configuration | X | |
| Cluster upgrade and migration | X | X |
| iSCSI Software Target integration | X | |
| Task Scheduler integration | X | |
| Windows PowerShell support | X | X |
Management of large-scale clusters by using Server Manager and Failover Cluster Manager
Failover Clustering in Windows Server 2012 supports up to 64 physical nodes and up to 4,000 virtual machines per cluster (and up to 1,024 virtual machines per node), compared with 16 physical nodes and 1,000 virtual machines per cluster in Windows Server 2008 R2. Both Server Manager and Failover Cluster Manager provide new capabilities in Windows Server 2012 to manage clusters at this scale.
Server Manager can discover and provide management capabilities for the nodes of the cluster. It enables remote multi-server management, remote role and feature installation, and the ability to start Failover Cluster Manager from the Server Manager GUI. For more information, see Manage Multiple, Remote Servers with Server Manager.
New Failover Cluster Manager features that simplify large-scale management of clustered virtual machines and other clustered roles include the following:
- Search, filtering, and custom views. Administrators can more easily manage and navigate large numbers of clustered virtual machines or other clustered roles.
- Multiselect. Administrators can easily select a specific collection of virtual machines and then perform any needed operation on them (such as live migration, save, shutdown, or start).
- Simplified live migration and quick migration of virtual machines and virtual machine storage. Live migration and quick migration are easier to perform.
- Simpler configuration of Cluster Shared Volumes (CSVs). Configuration is a simple right-click in the Storage pane. CSVs have additional enhancements, described in Cluster Shared Volumes, later in this topic.
- Support for Hyper-V Replica. Hyper-V Replica provides point-in-time replication of virtual machines between storage systems, clusters, and data centers for disaster recovery.
What value do these changes add?
These scalability features in Windows Server 2012 improve the configuration, management, and maintenance of large physical clusters and Hyper-V failover clusters.
Management and mobility of clustered virtual machines and other clustered roles
In Windows Server 2012, administrators can configure settings, such as the relative priority to start or place different virtual machines and other clustered roles on cluster nodes, to efficiently allocate resources to clustered workloads. The following table describes these settings:
| Setting | Description | Scope |
|---|---|---|
| Priority settings: High, Medium (the default), Low, or No Auto Start |
| All clustered roles, including clustered virtual machines |
| Preemption of virtual machines based on priority |
| Clustered virtual machines |
| Memory-aware virtual machine placement |
| Clustered virtual machines |
| Virtual machine mobility features |
| Clustered virtual machines |
| Automated node draining |
| All clustered roles, including clustered virtual machines |
What value do these changes add?
These features in Windows Server 2012 improve the allocation of cluster resources, particularly when starting or maintaining nodes, in large physical clusters and Hyper-V failover clusters.
Cluster Shared Volumes
Cluster Shared Volumes (CSVs) were introduced in Windows Server 2008 R2 to provide common storage for clustered virtual machines. In Windows Server 2012, CSVs can provide storage for additional clustered roles. CSVs allow multiple nodes in the cluster to simultaneously access the same NTFS file system without imposing hardware, file type, or directory structure restrictions. As shown in the following figure, with CSVs, multiple clustered virtual machines can use the same LUN and still live migrate or quick migrate from node to node independently.
Figure 1 Cluster Shared Volumes
The following is a summary of new CSV functionality in Windows Server 2012.
- Storage capabilities for a wider range of clustered roles. These include Scale-Out File Servers for application data, which can provide continuously available and scalable file-based (SMB) server application storage. For more information, seeSupport for Scale-Out File Servers later in this topic.
- CSV proxy file system (CSVFS). This file system provides cluster shared storage with a single, consistent file name space while still using the underlying NTFS file system.
- Support for BitLocker Drive Encryption. CSVs can be decrypted by using the common identity of the computer account for the cluster (also called the Cluster Name Object, or CNO). This enables physical security for deployments outside secure data centers and meets compliance requirements for volume-level encryption.
- Ease of file backup. CSVs support backup requestors that are running the Windows Server 2008 R2 operating system as well as Windows Server 2012 Backup. Backups can use application-consistent and crash-consistent Volume Shadow Copy Service (VSS) snapshots.
- Direct I/O for file data access, including sparse files. This enhances virtual machine creation and copy performance.
- Removal of external authentication dependencies. This improves the performance and resiliency of CSVs.
- Server Message Block (SMB) 3.0 integration. CSVs can provide storage for Hyper-V and applications such as Microsoft SQL Server. For more information, see Server Message Block overview.
- Integration with SMB Multichannel and SMB Direct. These new SMB features allow CSV traffic to stream across multiple networks in the cluster and to leverage network adapters that support Remote Direct Memory Access (RDMA).
- Storage can be made visible to only a subset of nodes. This feature enables cluster deployments that contain both application and data nodes.
- Integration with Storage Spaces. The Storage Spaces feature in Windows Server 2012 provides a mechanism to virtualized cluster storage on groups of inexpensive disks. It can integrate with CSVs to permit scale-out access to data. For more information, see Storage Spaces Overview.
- Ability to scan and repair volumes with zero offline time. The NTFS file system identifies, logs, and repairs anomalies without affecting the availability of CSVs.
What value do these changes add?
These new features provide easier CSV setup, broader workload support, enhanced security and performance in a wider variety of deployments, and greater file system availability.
What works differently?
CSVs now appear as CSV File System (CSVFS) instead of NTFS.
Support for Scale-Out File Servers
Scale-Out File Servers can host continuously available and scalable storage by using the SMB 3.0 protocol. Failover clusters in Windows Server 2012 provide the following foundational features that support this new type of file server:
- A Distributed Network Name (DNN) that provides an access point for client connections to the Scale-Out File Servers.
- A Scale-out File Server resource type that supports Scale-out File Services.
- Cluster Shared Volumes (CSVs) for storage. For more information, see Cluster Shared Volumes earlier in this topic.
- Integration with File Services features to configure the clustered role for the Scale-Out File Server, in addition to the general file server clustered roles.
What value do these changes add?
These features support continuously available and readily scalable file services for applications and for end users. For more information, see Scale-Out File Server for Application Data Overview.
Cluster-Aware Updating
Cluster-Aware Updating (CAU) is an automated feature that allows updates to be applied automatically to the host operating system, or other system components, in clustered servers while maintaining availability during the update process. This feature leverages automated draining and failback of each node during the update process. By default, it uses the Windows Update Agent infrastructure as its update source. For an overview of the CAU feature, see Cluster-Aware Updating overview.
What value does this change add?
CAU provides increased uptime of high availability services, ease-of-maintenance of failover clusters, and reliability and consistency of IT processes.
Virtual machine application monitoring and management
In clusters running Windows Server 2012, administrators can configure monitoring of services on clustered virtual machines that are also running Windows Server 2012. This functionality extends the high-level monitoring of virtual machines that is implemented in Windows Server 2008 R2 failover clusters. If a monitored service in a virtual machine fails, the service can be restarted, or the clustered virtual machine can be restarted or moved to another node (depending on service restart settings and cluster failover settings).
What value does this change add?
These features increase the uptime of high availability services that are running on virtual machines within a failover cluster.
Cluster validation tests
The Validate a Configuration Wizard in Failover Cluster Manager simplifies the process of validating hardware and software across servers for use in a failover cluster. The performance for large failover clusters has been improved, and new tests have been added.
The following are improved features of validation:
- Improved performance: Validation tests, especially storage validation tests, run significantly faster.
- Targeted validation of new LUNs. Administrators can test a specific new LUN (disk), rather than testing all LUNs every time they test storage.
- Integration of validation with WMI. Applications and scripts can programmatically consume cluster validation status is through Windows Management Instrumentation (WMI).
- New validation tests. The new tests for CSVs and for Hyper-V and virtual machines (when the Hyper-V role is installed) complement the functionality introduced in Windows Server 2012.
- Validation test awareness of replicated hardware. These validation tests help support multi-site environments.
What value do these changes add?
The added validation tests help confirm that the servers in the cluster will support smooth failover, particularly of virtual machines from one host to another.
Active Directory Domain Services integration
Integration of failover clusters with Active Directory Domain Services (AD DS) is made more robust in Windows Server 2012 by the following features:
- Ability to create cluster computer objects in targeted organizational units (OUs), or by default in the same OUs as the cluster nodes. Failover cluster dependencies on AD DS align with the delegated domain administration model that is used in many IT organizations.
- Automated repair of cluster virtual computer objects (VCOs) in case they are deleted accidentally.
- Cluster access only to read-only domain controllers. This supports cluster deployments in branch office or perimeter network scenarios.
- Ability of the cluster to start with no AD DS dependencies. This configuration enables certain virtualized data center scenarios.
Quorum configuration
The following features in Windows Server 2012 provide enhanced support in managing the cluster quorums:
- Simplified Quorum Configuration Wizard. The Quorum Configuration Wizard has been simplified and integrates well with both new features and existing quorum functionality.
- Assign votes to nodes. The administrator can specify which nodes have votes in determining quorum (by default, all nodes have a vote).
- Dynamic quorum. With dynamic quorum, cluster administrators can now automatically manage the quorum vote assignment for a node based on the state of the node. This feature increases the availability of the cluster in more scenarios than previously.
Cluster upgrade and migration
Using the updated Migrate a Cluster Wizard in Windows Server 2012, administrators can migrate the configuration settings for clustered roles (formerly called clustered services and applications) from clusters that are running Windows Server 2008, Windows Server 2008 R2, or Windows Server 2012. Migration enhancements in Windows Server 2012 include the following:
- Export and re-import of Hyper-V virtual machines.
- Migration to CSV disks.
- Mapping of storage and virtual networks.
- Reuse of existing storage.
What value does this change add?
The Migrate a Cluster Wizard provides ease and flexibility for the deployment, upgrade, and migration of failover clusters.
iSCSI Software Target integration
The Microsoft iSCSI Software Target is an integrated feature in Windows Server 2012. It can provide storage from a server over a TCP/IP network, including shared storage for applications that are hosted in a failover cluster. In Windows Server 2012, a highly available iSCSI Target Server can be configured as a clustered role by using Failover Cluster Manager or a Windows PowerShell cmdlet.
What value does this change add?
iSCSI Software Target helps provide economical, highly available storage.
Task Scheduler integration
The Task Scheduler is integrated with Failover Clustering in Windows Server 2012. The administrator can configure scheduled tasks in the cluster in three ways:
- Cluster-wide. The task is scheduled on all cluster nodes.
- Any node. The task is scheduled on a single, random node.
- Resource specific. The task is scheduled only on a node that owns a specified cluster resource.
Windows PowerShell support
New Windows PowerShell cmdlets support capabilities in Failover Clustering in Windows Server 2012 including the following:
- Managing cluster registry checkpoints, including cryptographic checkpoints.
- Creating Scale-Out File Servers.
- Monitoring of virtual machine applications.
- Updating the properties of a Distributed Network Name resource.
- Creating and managing clustered tasks.
- Creating a highly available iSCSI Target Server.
 Note |
|---|
| To use the Failover Clustering Windows PowerShell cmdlets, you must install the Failover Cluster module for Windows PowerShell that is included with the Failover Clustering Tools. For a complete list of the cmdlets, see Failover Clustering Cmdlets in Windows PowerShell. |
What value does this change add?
The new Windows PowerShell cmdlets provide management and scripting support for the new Failover Clustering features in Windows Server 2012.
What works differently?
The Test-ClusterResourceFailure cmdlet replaces Fail-ClusterResource.
Removed or deprecated functionality
- The Cluster.exe command-line tool is deprecated, but it can be optionally installed with the Failover Clustering Tools. Failover Clustering Windows PowerShell cmdlets provide functionality that is generally equivalent to Cluster.exe commands. For more information, see Mapping Cluster.exe Commands to Windows PowerShell Cmdlets for Failover Clusters.
- The Cluster Automation Server (MSClus) COM interface is deprecated, but it can be optionally installed with the Failover Clustering Tools.
- Support for 32-bit cluster resource DLLs is deprecated, but 32-bit DLLs can be optionally installed. Cluster resource DLLs should be updated to 64-bit.
- The Print Server role is removed from the High Availability Wizard, and it cannot be configured in Failover Cluster Manager.
- The Add-ClusterPrintServerRole cmdlet is deprecated, and it is not supported in Windows Server 2012.
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