You design a Business Intelligence (BI) solution by using SQL Server 2008. The solution will support a Microsoft ASP.NET application that is deployed to a Web farm. Reports will be deployed to a SQL Server 2008 Reporting Services (SSRS) instance. The databases for the SSRS instance will be deployed to a two-node failover cluster that hosts a single instance of SQL Server 2008.
You need to ensure that the SSRS instance remains available even when one of the servers fails.
What should you do?

A.
Configure SSRS for native server mode.

B.
Configure SSRS for integrated server mode.

C.
Deploy SSRS on the primary node of the cluster.

D.
Deploy SSRS in a scale-out deployment on the Web farm.

Explanation:
Tip: "failover cluster" = "Web farm"

Scaling Out
The Enterprise edition of SSRS supports scaling outthat is, using more than one physical machine to support the particular SSRS solution that runs from a common database. To implement a scaled-out solution, you use the Reporting Services Configuration Manager tool (Scale-Out Deployment section). This is also called a Web farm. SSRS is not a clusteraware application; this means that you can use network load balancing (NLB) as part of your scale-out deployment.
A typical scaled-out SSRS implementation includes multiple physical servers. Some of these servers distribute the front-end report rendering via a network load balancing type of scenario.
You can also add more physical servers to perform snapshots or caching in enterprisesized implementations.
(Smart Business Intelligence Solutions with Microsoft SQL Server 2008, Copyright 2009 by Kevin Goff and Lynn Langit)

http://technet.microsoft.com/en-us/library/ms157293.aspx
Planning a Deployment Topology
Standard Scale-Out Server Deployment
In a standard scale-out server deployment, multiple report servers share a single report server database. The report server database should be installed on a remote SQL Server instance.
Deploy Reporting Services in a scale-out deployment to provide a highly available and scalable report server installation. In a scale-out deployment, each report server in the deployment is referred to as a node. Nodes participate in the scale-out if the report server is configured to use the same report server database as another report server. Report server nodes can be load balanced to support high-volume interactive reporting.
A scale-out server deployment configuration is recommended in the following circumstances:
– For high-volume reporting, where activity is measured in concurrent users or in the complexity of reports that take a long time to process or render.
– For high-availability scenarios, where it is important that the reporting environment does not encounter unplanned downtime or become unavailable.
– When you want to improve the performance of scheduled operations and subscription delivery.
Scale-out deployment is not supported in all editions of SQL Server. All report server nodes in a deployment must run the same version and service pack level of SQL Server.