BizTalk Server: Host Architecture

Host architecture

BizTalk has by default two types of hosts, the in-process and isolated. The hosts are set in the database and creates corresponding tables and rows in the BizTalk databases so the host instances can process data. For the servers you create host instances, these instances perform jobs, either orchestrating, receiving files or sending them out. A host instance also performs the job to moves tracking data from the message box to the tracking database.

Isolated host

Isolated hosts primarily host adapters that must run outside of the normal BizTalk Server runtime process. For example, you use isolated hosts to host adapters for external processes such as ISAPI extensions and ASP.NET.

Isolated hosts have the following characteristics:

You cannot enlist orchestrations into an isolated host.

An isolated host cannot host send handlers.

An isolated host can host only the receive handlers associated with HTTP/S and SOAP adapters (the isolated-type adapters).
An isolated host cannot host tracking.
An isolated host cannot be the default host.
The status of an isolated host is always Status Unavailable. BizTalk Server does not access the status information for external processes.

In-process host

In-process hosts represent service instances that an administrator creates, deletes, and fully controls with WMI and the BizTalk Administration console.

In-process hosts have the following characteristics:

You can enlist any orchestration into an in-process host.

An in-process host can host only the receive handlers associated with File and MSMQT adapters (the in-process-type adapters).
The first in-process host you create in a BizTalk Server 2004 deployment is the default host and you cannot delete it. The BizTalk Message Queuing adapter uses the default host for static handler configuration. Adding an adapter automatically creates receive and send ports for the default host.

Dedicated hosts

The term dedicated hosts are brought up every now and then. Dedicated hosts performs dedicated tasks, and makes it easier to both control and have creates a better overview of you environment configuring throttling and thresholds is also a lot easier when you have split them up, also take a look at. BizTalk Host naming convention

Dedicated send hosts

Dedicated send hosts are hosts primarily dedicated to sending out information from BizTalk. By creating dedicated send hosts you can easier filter these from the host instances. Limiting or granting extra usage of server resources if this host send out many files after a debatch etc. This host should NOT have the option “Allow host tracking” turned on, since this host should not move tracking data from the message box to the tracking database.

Dedicated receive host

The same goes for the dedicated receive hosts. By limiting this host to only receive information for BizTalk you can also change the throttling settings and threshold for this host to fit it better for the amount of traffic going through it. This host should NOT have the option “Allow host tracking” turned on, since this host should not move tracking data from the message box to the tracking database.

Dedicated Orchestration host

The dedicated orchestration host should only be run for orchestration. Same goes for this one as for the two above. Altering settings and setting thresholds dedicated for this host and its purpose. This host should NOT have the option “Allow host tracking” turned on, since this host should not move tracking data from the message box to the tracking database.

Dedicated Tracking host

This host however is maybe one of the more important once. It is the host dedicated to move tracking data from the message box to the tracking database. This host however should have the option “Allow host tracking” checked. And should never run any receive location, orchestration or send ports. It should primarily only move tracking from the message box to the tracking database.