URL Reservations for Multi-Instance Report Server Deployments
If you install multiple instances of Reporting Services on the same computer, you must consider how you will define the URL reservations for each instance. Within each instance, the Report Server Web service and Report Manager must have at least one URL reservation each. The entire set of reservations must be unique in HTTP.SYS.
Duplicate URLs are detected during URL registration, which occurs when the service starts. If you create URL reservations that are not unique, the name conflict might not be detected until you start the service. For this reason, make sure that you follow naming conventions or rules to ensure all values are unique.
Reporting Services can be installed within a SQL Server named instance. When you install or configure a report server within a named instance, the instance name is automatically included in the virtual directory in the default URL reservation that Reporting Services provides. The following table shows the URL reservations for a default instance and a named instance.
SQL Server Instance
Default URL Reservation
For the named instance, the virtual directory includes the instance name. Both the default instance and the named instance listen on the same port, but the unique virtual directory names determine which report server gets the request.
Best practice recommendations are to use the virtual directory name to distinguish among the report server instance. It provides a clear correspondence between a URL and the target instance, and ensures that the application names are unique across the whole system.
Although using the instance name is recommended, you can use the URL syntax and your own naming conventions to meet the unique name constraints for URL reservations. The following examples illustrate different approaches for creating unique URLs for each instance.
Report Server default instance (MSSQLSERVER)
Each instance listens on a different port.
Each instance responds to different server names (fully qualified domain name, and machine name).
The underlying technologies used by Reporting Services impose requirements around unique names. HTTP.SYS requires that all URLs within its repository be unique. You can vary the port, host name, or virtual directory name to create a unique URL. ASP.NET requires that application identities be unique within the same process. This requirement affects the virtual directory names. It specifies that you cannot duplicate a virtual directory name within the same report server instance.