How many Web Dispatchers do I need?
SAP Web Dispatcher supports multiple systems to be served by a single SAP Web Dispatcher executable. See "Virtual Hosting Options" above for a description of how to configure such a setup. Reasons for using separate SAP Web Dispatcher installations could be:
- Load – SAP Web Dispatcher scales well on hardware with multiple cores. Using parallel SAP Web Dispatcher installations on parallel hosts is necessary only in scenarios with very high load.
- Administration and lifecycle management – It makes sense to use separate SAP Web Dispatchers for dev, test and prod landscapes to keep the latter as stable as possible while the former can be changed to support different scenarios or updated to newer versions more frequently. Mostly two installations are sufficient, one for prod and one for the rest. SAP Web Dispatcher is downward compatible and therefore changes usually don't affect other systems very strongly.
- Security – If one landscape or system needs to be as operated in strong isolation from other systems, it makes sense to use a separate SAP Web Dispatcher for that system or landscape.
- Virtual hosting – If you want to use IP-based or port-based virtual hosting (see above) then you can chose whether to use a single or multiple Web Dispatchers. For name-based virtual hosting usually all names point to the same Web Dispatcher, which decides based on the Host header to which backend system the request is routed.
You also have the option to configure the Web Dispatcher for multiple systems. This is explained in the below Wiki page.
Configuring the Web Dispatcher for Multiple Systems - Clarifications and Examples