Configuring a Dedicated Tracking Host
BizTalk Server is optimized for throughput, so the main orchestration and messaging engines do not actually move messages directly to the BizTalk tracking or BAM databases, as this would divert these engines from their primary job of executing business processes. Instead, BizTalk Server leaves the messages in the MessageBox database and marks them as requiring a move to the BizTalk Tracking database. A background process (the tracking host) then moves the messages to the BizTalk Tracking and BAM databases.
A BizTalk Host that hosts tracking is responsible for moving the DTA and BAM tracking data from the MessageBox database to the BizTalk Tracking (DTA) and BAM Primary Import databases. This movement of tracking data has an impact on the performance of other BizTalk artifacts running in the same host that is hosting tracking. Thus, you should use a dedicated host that does nothing but host tracking.
Using a dedicated tracking host also allows you to stop other BizTalk hosts without interfering with BizTalk Server tracking. The movement of tracking data out of the MessageBox database is critical for a healthy BizTalk Server system. If the BizTalk Host responsible for moving tracking data in the BizTalk group is stopped, the Tracking Data Decode service will not run. The impact of this is as follows:
HAT tracking data will not be moved from the MessageBox database to the BizTalk Tracking database.
BAM tracking data will not be moved from the MessageBox database to the BAM Primary Import database.
Because data is not moved, it cannot be deleted from the MessageBox database.
When the Tracking Data Decode service is stopped, tracking interceptors will still fire and write tracking data to the MessageBox database. If the data is not moved, this will cause the MessageBox database to become bloated, which will impact performance over time. Even if custom properties are not tracked or BAM profiles are not set up, by default some data is tracked (such as pipeline receive / send events and orchestration events). If you do not want to run the Tracking Data Decode service, turn off all tracking so that no interceptors save data to the database. To disable global tracking, see "How to Turn Off Global Tracking" in BizTalk Server 2006 R2 Help at http://go.microsoft.com/fwlink/?LinkId=101589. Use the BizTalk Server Administration console to selectively disable tracking events.
This host should be run on at least two computers running BizTalk Server (for redundancy in case one fails). For optimal performance, you should have at least one tracking host instance per MessageBox database. The actual number of tracking host instances should be N + 1, where N = the number of MessageBox databases. The "+ 1" is for redundancy, in case one of the computers hosting tracking fails.
A tracking host instance moves tracking data for specific MessageBox databases, but there will never be more than one tracking host instance moving data for a specific MessageBox database. For example, if you have three MessageBox databases, and only two tracking host instances, then one of the host instances needs to move data for two of the MessageBox databases. Adding a third tracking host instance distributes the tracking host work to another computer running BizTalk Server. In this scenario, adding a fourth tracking host instance would not distribute any more tracking host work, but would provide an extra tracking host instance for fault tolerance.
For more information about the BAM Event Bus service, see the following topics in BizTalk Server 2006 R2 Help: