Overview
Server availability is a higher priority than ever. The demands of a “24×7” global marketplace mean downtime can equate to lost customers, revenue, and productivity.
Windows Server 2008 brought many new or enhanced configuration, management, and diagnostic features to failover clustering that made setting up and managing the clusters easier for IT staff. Windows Server 2008 R2 builds on that work with improvements aimed at enhancing the validation process for new or existing clusters, simplifying the management of clustered virtual machines (which run with Hyper-V), providing a Windows PowerShell interface, and providing more options for migrating settings from one cluster to another. These enhancements combine to provide you with a near turn-key solution for making applications and services highly available.
Cluster Validation Tool
By using the Cluster Validation Tool, you can perform tests to determine whether your system, storage, and network configuration is suitable for a cluster. The Cluster Validation Tool verifies that the nodes meet all of the operating system requirements, that the networks are configured correctly, that there are at least two separate networks on each node for redundancy, and that the storage subsystem supports clustering.
Cluster Setup
Once validated by the Cluster Validation Tool, the installation has been streamlined so that administrators can set up a cluster in just a few clicks. The cluster installation is completely scriptable, enabling administrators to automate cluster deployments.
Cluster Migration
When migrating a clustered service setting can be captured and copied to another cluster. This reduces the time it takes to build the new cluster and configure the services. Administrators can migrate cluster workloads currently running on Windows Server 2003 and Windows Server 2008 to Windows Server 2008 R2. The migration process supports every workload currently supported on Windows Server 2003 and Windows Server 2008.
Cluster Management and Operations
The cluster management interface has been optimized to make managing the cluster easier and more intuitive. Cluster management can be performed from the command line as well as the Windows Management Instrumentation (WMI) management console.
Cluster Backup and Restore
Full integration with the Volume Shadow Copy Service makes it easier to back up and restore cluster configurations.
Cluster Infrastructure
With Windows Server 2008 R2, you can configure a cluster so that the quorum resource, which contains the cluster configuration settings, is not a single point of failure.
Cluster Storage
Administrators have better control and can achieve better performance with storage than was possible in previous releases. Failover clusters now support GUID partition table (GPT) disks that can have capacities of larger than 2 terabytes, for increased disk size and robustness. Administrators can now modify resource dependencies while resources are online, which means they can make an additional disk available without interrupting access to the application that will use it. And administrators can run tools in Maintenance Mode to check, fix, back up, or restore disks more easily and with less disruption to the cluster.
Cluster Network
Networking has been enhanced to support Internet Protocol version 6 (IPv6) as well as Domain Name System (DNS) for name resolution, removing the requirement to have WINS and NetBIOS name broadcasts. Other network improvements include managing dependencies between network names and IP addresses: If either of the IP addresses associated with a network name is available, the network name will remain available. Because of the architecture of Cluster Shared Volumes (CSV), there is improved cluster node connectivity fault tolerance that directly affects Virtual Machines running on the cluster. The CSV architecture implements a mechanism, known as dynamic I/O redirection, in which I/O can be rerouted within the failover cluster based on connection availability.
Cluster Security
Internet Protocol security (IPsec) can be used between clients and the cluster nodes, as well as between nodes so that you can authenticate and encrypt the data. Access to the cluster can also be audited to determine who connected to the cluster and when.
Benefits
Windows Server Failover Clustering is an important feature of the Windows Server platform that can help improve your server availability. When one server fails, another server begins to provide service in its place. This process is called failover. Failover clusters in Windows Server 2008 R2 provide you with seamless easy-to-deploy high availability for important databases, messaging servers, file and print services, and virtualized workloads.
With failover clustering you can help build redundancy into your network and eliminate single points of failure. The improvements to failover clustering in Windows Server 2008 R2 are aimed at simplifying clusters, making them more secure, and enhancing cluster stability.
Ahmed Gad 