When do you use BizTalk Mapper Activity inside of WF4 instead of BizTalk Engine?

Question

I've seen that BizTalk 2010 supports the new Mapper Activity for Workflow Foundation (From here: Easy use of mapper and LOB Adapters in WF Designer for AppFabric Applications). The dependency seems to be tied to the AppFabric (hence - IIS?). The question is under what circumstances would you use the mapper activity external from the BizTalk Engine? What advantages does hosting the mapper inside WF Runtime/AppFabric provide that hosting inside of the BizTalk Engine does not? Why not just call a BizTalk Orchestration Web Service directly?

Answer 1

BizTalk is a robust and reliable platform that hosts your Business Processes and performs transformations. To this end, it includes a SQL Server database that, among other things, provide persistance to ensure resilience in the face or hardware failures or software crash.

Because of this, BizTalk processes are considered heavyweight and it is usually difficult to achieve very low latency with BizTalk.

On the contrary, WF workflows hosted in IIS do usually provide lower latencies than BizTalk equivalent. However, WF does not provide, out of the box, a streaming XSLT transform engine, suitable for processing large messages without exhausting all available server resources.

That is why using the efficient streaming BizTalk mapper inside a lightweight WF workflow that does not incur the perdormance overhead of being persisted to the database makes sense in certain cases.

Answer 2

If you already run BizTalk, then there is not much of a point to using WF, AppFabric, and just the BizTalk Mapper. This feature seems to mostly be for those who are not running (and perhaps do not want to run) BizTalk, especially those who have everything in IIS already.

WF in IIS is certainly a lot more lightweight. Here is one walk-through that covers the that basic benefit in using workflow and the mapper: http://seroter.wordpress.com/2011/04/03/using-the-biztalk-adapter-pack-and-appfabric-connect-in-a-workflow-service/

The annoying part of this arrangement, however, is that you must have the (licensed) BizTalk runtime installed. As you probably know, a BizTalk license isn't cheap.

[speculation]Going forward, I anticipate that we will see more and more BizTalk functionality ported over to the IIS/AppFabric world, so that eventually (say in 10 years) BizTalk can go away (assuming we aren't all forced off our own servers and onto the cloud, which could also happen). This is just an early step in that direction.[/speculation]