Providing high availability to mission-critical applications, services, and data is a primary objective of successful IT departments. When services are down or fail, business continuity is interrupted, which can result in significant losses. Windows Server 2008 R2 supports many key high-availability features to help organizations meet their uptime requirements for their critical systems such as Failover Clustering, Network Load Balancing (NLB), Shadow Copy, Windows Server Backup and a new Windows Recovery Environment.
Failover clustering can help you build redundancy into your network and eliminate single points of failure. Learn more at our extensive
Failover Clustering site.
Failover Clustering site.
Network Load Balancing
Network Load Balancing (NLB) allows you to distribute TCP/IP requests to multiple systems in order to optimize resource utilization, decrease computing time, and ensure system availability. NLB has been improved in Windows Server 2008 R2, including:
Windows Hardware Error Architecture (WHEA)
Windows Hardware Error Architecture (WHEA) has been enhanced to support Machine Check Architecture (MCA) error recovery, offering the ability to contain and recover from several types of multi-bit ECC errors in memory and cache without operating system or application interruption. For more details please visit TechNet http://www.microsoft.com/whdc/system/pnppwr/whea/default.mspx .
Dynamic Hardware Partitioning
On a dynamically partitionable server, partition units can be added or replaced without restarting the operating system. Windows Server 2008 R2 supports hot-add of processors, memory, and I/O host bridges, and hot-replace of processors and memory on x64-based and Itanium-based systems which support DHP.
Fault Tolerant Hardware
Windows Server 2008 R2 includes support for fault tolerate memory synchronization. Fault-tolerant servers contain redundant hardware – from fans and power supplies, to processors and RAM, which run in lockstep with each other. If a primary component fails, the secondary component takes over in a process that is seamless to the application running on the server.
Windows Server 2008 R2 scales to 256 logical processors, for business-critical servers supporting large databases, line of business, and custom applications which sometimes require highly reliable, scalable servers.
Increased Workload Support by Scaling Out
The Network Load Balancing feature in Windows Server 2008 R2 allows you to combine two or more computers into a cluster. You can use NLB to distribute workloads across the cluster nodes in order to support a larger number of simultaneous users. Network Load Balancing feature improvements in Windows Server 2008 R2 include:
- Improved Support for Applications and Services That Require Persistent ConnectionsThe IP Stickiness feature in Network Load Balancing allows you to configure longer affinity between client and cluster nodes. By default, Network Load Balancing distributes each request to different nodes in the clusters. Some applications and services, such as a shopping cart application, require that a persistent connection be maintained with a specific cluster node.
- Improved Health Monitoring and Awareness for Applications and ServicesThe Network Load Balancing Management Pack for Windows Server 2008 R2 allows you to monitor the health of applications and services running in Network Load Balancing clusters.
- Next Generation TCP/IPInternet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) are both supported natively by Windows Server 2008 R2. NLB extends full support to IPv6 for all communication while maintaining IPv4 support.
- Multiple IP Address SupportEach node in your NLB cluster can now have multiple dedicated IP addresses.
- Microsoft ISA Server IntegrationMicrosoft ISA Server can support your mixed IPv4 and IPv6 infrastructure by allowing multiple IP addresses for each NLB node where IPv4 and IPv6 clients are used. ISA Server can also provide intrusion detection services to protect your NLB cluster.
Learn more about NLB at the HA Windows Server TechCenter.
Shadow Copy, Windows Server Backup and Windows Recovery
Windows Server 2008 R2 contains new and updated features to help you create backups and, if needed, perform a recovery of your operating system, applications, and data. By using these features appropriately and implementing good operational practices, you can improve your organization's ability to recover from damaged or lost data, hardware failures, and disasters.
There are several features in Windows Server 2008 R2 that you can use together to create backups and perform recoveries of your server systems and data. These include the following:
- Shadow Copies of Shared Folders
Shadow Copies of Shared Folders provides point-in-time copies of files that are located on shared resources, such as a file server.
- Windows Server Backup tools
Windows Server Backup is a feature in Windows Server 2008 R2 that provides a set of wizards and other tools for you to perform basic backup and recovery tasks for your servers running Windows Server 2008 R2. This feature has been redesigned and introduces new technology.
- Windows Recovery Environment
Windows Recovery Environment in Windows Server 2008 R2 is a partial version of the operating system and a set of tools that you can use to perform operating system or full server recoveries (along with a backup that you created earlier using Windows Server R2 Backup).
Learn more about the features at the Backup and Recovery Windows Server TechCenter.
Improved Storage Solution Availability
Availability of storage is essential to all mission-critical applications in your organization. Windows Server 2008 R2 includes the following improvements to storage solution availability:
- Improved Fault Tolerance Between Servers and Storage.When multiple paths exist between servers and storage, Windows Server 2008 R2 can failover to an alternate path if the primary path fails. You can select the failover priority by configuring the load-balancing policies for your storage solution.
- Improved Recovery from Configuration Errors.An error in the configuration of the storage subsystem can negatively affect storage availability. Windows Server 2008 R2 allows you to take configuration snapshots of the storage subsystem (for example, the iSCSI configuration). In the event of a subsequent configuration failure, you can quickly restore the configuration to a previous version.