The smallest available BizTalk Server 2006 deployment is made up of two computers that have an active/active cluster configuration for SQL Server. Both computers contain instances of all the BizTalk Hosts in the environment. If one computer fails or encounters errors, the other computer maintains service availability for both SQL Server and BizTalk Server. This configuration is not highly available because you cannot cluster the master secret server. For more information about clustering the master secret server, see High Availability for Enterprise Single Sign-On.

For small BizTalk Server 2006 deployments that contain fewer than five computers, we recommend that the SQL Server cluster that contains the BizTalk Server databases runs on separate computers from the BizTalk Server computers. The BizTalk Server computers can run all the BizTalk Hosts (receive, process, and send). To make this deployment highly available, cluster the SQL Server and the Enterprise Single Sign-On master secret server, and have two BizTalk Servers, each running an instance of each host in your environment.

The following figure shows a small BizTalk Server deployment that is highly available.

For medium-sized deployments that contain five to ten computers, we recommend that you cluster the SQL Server that contains the BizTalk Server databases and the Enterprise Single Sign-On master secret server. If your scenario is receive-intensive, you may want to dedicate two BizTalk Servers to run the receiving host instances to provide a highly available solution. You can then have two more computers that are running both the processing and send host instances. To make this a highly available deployment, create host instances of both the processing and send hosts on two BizTalk Servers. Similarly, if you have a processing-intensive scenario, you may want to dedicate two BizTalk Servers to run the processing host instances, and have the remaining two BizTalk Servers running instances of both the receive and send hosts.

The following figure shows a highly available medium-sized BizTalk Server deployment with two BizTalk Servers dedicated to receiving operations.

For more information about high availability for Enterprise Single Sign-On, see High Availability for Enterprise Single Sign-On.

For large-scale deployments that contain 10 or more computers, dedicate separate BizTalk Server computers for the receiving, processing, and sending functions. Also, if you have many BizTalk Server computers in a group, you can include additional MessageBox database computers to increase performance. In this case, cluster the MessageBox databases and the master secret server to provide high availability.

Such a distributed configuration demonstrates the flexibility of BizTalk Server 2006 because it lets you to evaluate and identify specific points of failure in your deployment, and then strategically allocate resources to reduce those points in the system. Today's dynamic business environment demands such flexibility because workload fluctuations and business requirements can change daily.

Instead of spending additional money to upgrade or acquire new hardware, you can use existing resources to achieve high availability by moving resources from computers that consume few resources to computers that are resource-intensive.

The following figure shows a large-scale BizTalk Server 2006 deployment.

For more information about high availability for Enterprise Single Sign-On, see High Availability for Enterprise Single Sign-On.

Concepts