NLB Applications and Services

NLB is well equipped to distribute user connections and create fault tolerance for a number of different applications and network services. Because NLB does not replicate data across cluster nodes—and neither does failover clustering for that matter—using applications that require access to local data that is dynamic or frequently changes is not recommended for NLB clusters.

Applications well suited for NLB clusters are web-based applications and services, proxy services, virtual private network, SMTP gateways, streaming media, and Remote Desktop Services Session Host server systems. Many other applications and services can also run well on NLB clusters, but the preceding list is what most organizations utilize NLB clusters for.

NLB clusters are based on client connections made to a specific DNS name, IP address, and TCP and/or UDP port using either IPv4 or IPv6. It’s important to read the vendor’s application documentation regarding how the client communicates with the application and how this communication can be configured on load-balancing devices or services such as Microsoft Windows Server 2008 R2 NLB clusters. For instance, certain applications use cookies or other stateful session information that can be used to identify a client throughout the entire session and it is important that the client maintains a connection to the same cluster node during the entire session. Other applications, such as a website that serves up static pages, can respond to a single client’s requests from multiple nodes in the NLB cluster. For a web-based application, such as an e-commerce application, an encrypted SSL session, or an application that is authenticated by the actual web server, the NLB cluster would need to direct all communication between the client and a specific cluster node. Considering these types of scenarios in advance helps determine how the NLB cluster will be defined.


Installing the Network Load Balancing Feature
Before an NLB cluster can be created, the feature needs to be installed on all servers that will participate in the cluster. To install the Network Load Balancing feature, perform the following steps:

1. Log on to each Windows Server 2008 R2 system with an account that has local administrator rights.

2. Click Start, click All Programs, click Administrative Tools, and select Server Manager.

3. In the tree pane, select Features, and in the Actions pane, click the Add Features link.

4. On the Before You Begin page, click Next to continue.

5. On the Add Features page, check the box for Network Load Balancing, and click Next to continue.

6. On the Confirm Installation Selections page, review the list of features that will be added, and click Install to begin the installation.

7. On the Installations Results page, review the results, and click Close to return to
Server Manager.

8. Close the Server Manager console and log off of the server.

9. Log on and repeat this process on the remaining servers that will participate in the cluster as required.

Source of Information : Sams - Windows Server 2008 R2 Unleashed (2010)