Administering an ISP Installation

Clustering

Clustering allows two or more servers to appear to users as though they are one computer. The servers are connected not only physically by cables, but also programmatically through clustering software. This connection allows them to take advantage of features (such as fault tolerance and load balancing) that are unavailable to stand-alone server nodes. Clustered servers can also share disk drives that contain important information, such as a database.

If you have installed Windows 2000 Advanced Server, you already have software that will allow you to manage clustering. When linked together, Cluster Service and Network Load Balancing offer comprehensive availability and scalability for customers who are building applications with multiple tiers:

Cluster Service gives you reliable application, transactional, file, and printing services on a two-node cluster. When combined with Microsoft® SQL Server™ Enterprise Edition or Microsoft® Exchange Enterprise Edition, Cluster Service adds reliable database and messaging services to your installation.
Network Load Balancing extends the IIS 5.0 clustering technology in several ways. For example, in a multitier application, Network Load Balancing supplies load balancing and high availability for the first tier—the user interface. Because this kind of load balancing works through TCP/IP, a variety of workloads can benefit, including the load balancing of IIS 5.0 sessions, as well as Point-to-Point Tunneling Protocol (PPTP) and Virtual Private Network (VPN) sessions. Up to 32 servers can be formed into a Web cluster. Network Load Balancing is an extraordinary solution for the most demanding Web sites in the world, such as sites that need to support tens of thousands of simultaneous connections. Microsoft Web sites, including MSN (the third-busiest Web site in the world), prove the value of Network Load Balancing every day.

While Cluster Service reinforces the availability of database and messaging applications (back end), Network Load Balancing delivers reliability to IIS 5.0 Web servers (front end). For example, on an e-commerce Web site, you can cluster your front-end Web servers that are running IIS 5.0 with Network Load Balancing, and have them access a back-end cluster that is running SQL Server Enterprise Edition.

Additional features in Windows 2000 Advanced Server make it easy to set up and manage clustering on your installation. These features include:

Improved usability, including wizards for creating applications, setting up virtual servers, and configuring and managing clusters on your installation.
Failover of system services, including all existing services—Web, file, print, and Message Queuing—plus support for Dynamic Host Configuration Protocol (DHCP), Windows Internet Name Service (WINS), and distributed file system (DFS).
Orderly rolling upgrade to individual cluster nodes without taking the cluster, as a whole, offline.
Appropriate support for Windows Management Instrumentation (WMI) and the IIS snap-in, as well as integration with Microsoft® Active Directory™.
Network adapter failure detection and forced failover.
Plug and Play support for network adapters and disk drives (allowing hot swappable components to be replaced without shutting down the system).

All of these clustering components work together to greatly increase reliability through fault tolerance and load balancing. For details, see the “Replication and Clustering in IIS” topic in the IIS 5.0 online product documentation.