Clustering is an indispensible technique to achieve maximum fault tolerance. A cluster is a collection of computer systems responsible for running a shared set of applications and services. The systems in the cluster are interconnected through hardware and software in such a way that in case any component in the cluster stops functioning, the workload will "failover" to, or be assumed by, another system in the cluster without a disruption of service.
Failover clustering clearly has an advantage in increasing network availability in the case of a hardware breakdown, but it also allows non-disruptive system maintenance for environments that have no time window when key applications such as email or web commerce can be taken offline without hurting business. In the case of geographically dispersed environments, clustering provides insurance against widespread disasters such as earthquakes or hurricanes.
Enhanced-capability editions of Windows Server 2008 include significant improvements in failover clustering such as easier deployment, management, and migration; enhanced support for multi-site clusters; improved security architecture and quorum models; stronger authentication and encryption; and more efficient tools for backup and recovery.
Progent offers a full range of Windows Server 2008 Server consulting services and can assist businesses of any size to design, implement, and maintain cost-effective failover clusters that provide high availability, security, and performance and that add significantly to the business value of your information network.
New and Improved Features of Windows Server 2008 Failover Clustering
The failover clustering capabilities incorporated into Microsoft Windows 2008 Server represents more than a decade of Microsoft's realworld experience in developing clustering technology. The Enterprise and Datacenter Editions of Microsoft Windows Server 2008 offer a number of new clustering services and capabilities including:
More Convenient Management Interfaces
Windows Server 2008 includes Microsoft Management Console (MMC) 3.0, a new easy-to-use interface for controlling network resources. The new Failover Cluster Administration Console is task oriented rather than cluster resource oriented. To make a file share highly available, for example, the administrator no longer has to create a group, a disk resource, an IP address resource, Network Name, configure IsAlive/LookAlive, configure preferred services, and set dependencies. Instead, the wizard simply asks for the Network Name. You do not necessarily need to assign an IP address because Windows Server 2008 failover clustering now supports DHCP.
Windows Server 2008 also supports remote management via the Remote Server Administration Tools (RSAT). You can manage multiple clusters throughout the organization from a single MMC. Windows Server 2008 Failover Clusters are also fully scriptable with Windows Management Instrumentation (WMI).
Built-in Cluster Validate Tool
Windows Server 2008 clustering includes a cluster Validate Tool, an expanded and integrated version of the ClusPrep tool released for Windows Server 2003 server clustering. As a part of the cluster configuration process, Validate runs a set of tests to determine whether the selected servers, cluster networks, and storage meet the requirements for failover clustering. Validate performs an inventory that includes BIOS information, operating systems, adapters, drivers and software updates; verifies cluster topology for redundancy; checks IP configuration details; and makes sures that storage can correctly handle simulated cluster actions. The Validate Tool helps prevents configuration errors, which is one of the most common problems encountered in failover clusters.
Support for Windows Server 2008 Server Core
Windows Server 2008 offers a Server Core installation option that supports failover clustering and provides a bare-bones environment for running distinct server roles. By limiting the services that need to be maintained and updated, this minimalist installation reduces support and management expense and enhances security by shrinking the server's attack surface. Server Core supports a variety of important roles including DHCP server, file services, print services, DNS server, Active Directory Domain Services, streaming media services, and Windows Server 2008 virtualization.
Better Storage and Backup Support
Improvements in storage and backup offer increased stability and availability for failover clusters. Support for both Master Boot Record (MBR) and GUID Partition Table (GPT) disks allows the creation of disks greater than 2 terabytes. Built-in logic initiates self healing automatically as long as the system can find either the disk signature in the Master Boot Record or the SCSI inquiry page 0x83 data (VPD).
Support for Storage Area Networking (SAN) solutions is improved for storage hardware that supports SCSI-3 SPC3–compliant SCSI commands for persistent reservation/release. All multi-path solutions are Microsoft Multipath I/O (MPIO). The Device Specific Module (DSM) provided by the storage vendor is responsible for sending PR registration information down each path to the storage system. Closer integration with Volume Shadow Copy Service (VSS) makes the backup process easier. Failover clustering in Windows Server 2008 has its own VSS.
Greater Expandability
With Windows Server 2008, x64-based failover clusters support up to 16 nodes in a single cluster, as opposed to the maximum of 8 nodes in Windows Server 2003. Windows Server 2008 failover clusters also now support GPT disks, which use the GUID partition table (GPT) disk partitioning system. A GPT disk allows up to 128 primary partitions and a much larger volume size. In comparison, MBR disks can support up to four primary partitions and a volume size limit of up to 2 terabytes. For greater reliability, GPT disks offer replication and cyclical redundancy check (CRC) protection of the partition table. The increased number of nodes plus support for GPT disks dramatically extends the scalability of larger volumes in cluster environments.
A New Quorum Model
Windows Server 2008 introduces a new failover clustering quorum model that incorporates a combination of Microsoft's earlier shared disk and majority node set models. In Windows Server 2008 failover clustering there are now four ways to establish a quorum:
- No Majority – Disk Only (same as Windows Server 2003 shared disk quorum)
- Node Majority (same as the Windows Server 2003 majority node set)
- Node and Disk Majority
- Node and File Share Majority
The quorum mechanism in Windows Server 2008 no longer requires a shared storage resource for the cluster to function. Quorum now refers to a number of votes which must equate to a majority of nodes. All nodes and disk resources have a vote. This avoids failure points in the old model, which required the disk to be available at all times so that disk failure meant cluster failure.
An Improved Security Model
Windows Server 2008 failover clustering incorporates a new security model that enhances its security and dependability. Changes include:
- Elimination of the need for a domain user account for the Cluster Service Account (CSA)
- Better logging and event tracing
- Transition from unsecure datagram remote procedure call (RPC) communications to TCP-based RPC communications
- Default enabling Kerberos authentication on all cluster network name resources
- The ability to audit access to the cluster service via either the Failover Cluster Management snap-in or the cluster command-line interface
- Ability to secure Inter-Cluster communications.
New Networking Capabilities and More Flexible Dependencies
Windows Server 2008 failover clustering includes a new networking model. Major improvements include:
- Enhanced support for geographically distributed networks
- The ability to place cluster nodes on different networks
- The ability to use DHCP server to assign IP addresses to cluster interfaces
- Improvements in the cluster heartbeat mechanism
- New support for IPv6
Administrators no longer have to stretch virtual local area networks across the wide area network to support geographically dispersed servers on different subnets. Failover cluster nodes can now be located on different subnets. Individual cluster nodes can be placed on separate, routed networks, which allows IP Address and Network Name resources to come online when services and applications fail over to remote nodes.
Cluster IP address resources can now get their addressing from DHCP servers as well as from static entries. The cluster heartbeat mechanism has moved from a UDP broadcast health checking mechanism to a UDP unicast communication that it uses a Ping-like Request-Reply process. This allows better security and more reliable packet sequence numbering. Windows Server 2008 supports IPv6 IP Address resources and IPv4 IP Address resources either alone or in combination in a cluster. Clustering also supports 6-4 and Intra-site Automatic Tunneling Addressing Protocol (ISATAP).
How Progent Can Help You Benefit from Microsoft's Failover Clustering
Progent's Microsoft-certified consultants can help you evaluate the business benefits of Windows Server 2008 failover clustering, set up pilot programs to validate performance and compatibility for your key workloads, develop and execute a cost-effective deployment plan, train your IT staff to manage your clustering environment, and provide ongoing consulting and technical support services remotely or at your site. Progent can also provide comprehensive Help Desk services.
Progent's service professionals can also help you migrate from Windows Server 2003 cluster nodes. This migration requires experience because these two types of nodes cannot share the same cluster, which eliminates a rolling migration.
Progent's CISM, CISA, GIAC, and CISSP certified security engineers can assess the protection offered by your cluster environment and can recommend and implement affordable improvements. Progent's security experts can also help you design, document, and test business continuity and disaster recovery plans.
Other High Availability Solutions Provided by Progent's Experts
Progent's Microsoft and Cisco-certified consulting experts can assist your company build an affordable, fault-tolerant IT architecture that addresses critical challenges covering a broad array of networking solutions and operations such as:
Workplace Recovery Planning
Progent's business continuity engineers can show you how to create a workplace recovery strategy so you can restore IT functionality in the event of an IT system disaster. Progent can assist you to define a comprehensive disaster recovery strategy that incorporates scheduled disaster recovery evaluations and testing. Progent's Microsoft and Cisco-certified professionals can also help you create an affordable, zero-downtime network solution that takes into account availability issues involving a broad array of infrastructure technologies and processes. To read more, see Disaster Recovery Consulting Services.
Fault Tolerant Internet Connectivity
Progent's Cisco-authorized IT professionals can help you design an economical, fault tolerant Internet connection architecture that can achieve 24x7 Internet access via a broad array of fault tolerant Internet access technologies including fault tolerant BGP, automatic fail-over, and redundant Internet Service Providers. Progent can provide CCIE professionals to help you apply the most advanced technology for fault tolerant Internet connectivity to build an economical, completely redundant Internet interface with automatic failover and other features to deliver non-stop Internet availability. To read more, see Non-stop Internet Access Architecture.
High Availability Load Balancing
Progent offers high availability load balancing consulting that addresses system load balancing, load balanced programs, LAN/WAN backbone routing, and content delivery products including Cisco Content Engine. Non-stop load balancing products for which Progent can provide consulting services include Microsoft Windows Server 2003 and 2008 Network Load Balancing Manager, Citrix Metaframe and Presentation Server, Cisco Content Services Switch, Cisco Content Distribution Manager and Cisco CDN Software, and F5 Networks 3-DNS. To find out more, visit Fault Tolerant Load Balancing.
High-Availability Colocation
Progent's Data Center professionals can help you find fault-tolerant data centers that match the specific requirements of your business. High availability off-site data centers are particularly attractive to small organizations due to of their low cost and convenience compared to taking a do-it-yourself approach. Trying to build an in-house data center with even a basic degree of fault tolerance is too expensive for most small companies. Progent can help you reap all the advantages of high-availability colo sites by offering a complete range of engineering and support services. For more information, visit High-Availability Data Centers Expertise.
Failsafe Branch Office Networking
Progent’s interoffice network infrastructure engineers can help small organizations achieve zero-downtime interoffice connections through redundant networks featuring automatic failover. Progent’s Cisco-certified CCIE engineers can plan and implement high-availability Inter-office connections based on fault tolerant EIGRP routers or non-stop OSPF configurations of Cisco routers. Progent can demonstrate how redundant connectivity and automatic fail-over can provide economical 24x7 interoffice networking. To learn more, visit Non-stop Inter-office Connectivity.
Microsoft Data Protection Manager (DPM) Data Recovery Consulting Services
Progent's certified Data Protection Manager (DPM) support professionals can assist you to develop a practical business continuity plan, design an affordable high-availability IT architecture, install a Microsoft DPM-powered backup and restore system, thoroughly validate your DPM system, educate your IT staff or regular service providers how to maintain Microsoft DPM, or provide complete IT support outsourcing such as remote housing of Microsoft DPM servers in Progent's secure data center. For more information, see System Center Data Protection Manager Expertise.
Why Pick Progent for Workplace Recovery Planning and Fault-tolerant Networking Consulting?
Because Progent is a Microsoft Gold Certified Partner and offers high-level application consulting for a broad variety of small business applications, Progent is able to help clients to arrive at efficient IT solutions that maximize the business value of your network. As a Registered Partner for Cisco, Progent can provide the expertise of certified consultants and specialists with expertise in architecting, installing and managing networking environments based on Cisco Systems technology. The breadth of Progent's technical know-how and Progent's appreciation for the needs of small companies make Progent the ideal partner for building and maintaining a cost-effective, high-availability network.
How to Get Help from Progent's Engineers for Non-stop Network Support
If you wish to ask Progent about professional assistance for high availability infrastructure, phone 1-800-993-9400 or email fault-tolerant-help@progent.com.
