Scaling Your Solutions

BizTalk Server architecture provides a very good support for scalability. The scaling patterns that you choose depend on complexity of your scenario, hardware and the throughput/Latency requirements. You should start with a smaller topology initially and try to scale-up or down based on the guidelines in this section.

Scaling Out and Scaling Up

There are two ways to scale your BizTalk Server system:

  • Scaling-out is the process of adding additional computers. For example, if BizTalk Server is bottlenecked by CPU resources, adding another server provides double the CPU resources which may provide double the throughput.

  • Scaling-up is process of upgrading the existing computer. For example, you can upgrade a BizTalk Server computer from a 4 processor machine to an 8 processor.

    A BizTalk Server system has two tiers: the BizTalk Server tier and the SQL Server tier, which contains your MessageBox databases. In any scenario, you can scale out or scale up each tier. That is, you can scale-out BizTalk Server and the MessageBox database, or scale up both of them.

    In most cases, the BizTalk tier becomes a bottleneck first, and you start improving performance by scaling it out. But, at some point, depending on complexity of your system and the hardware you use, you can’t scale out the BizTalk tier anymore and the SQL Server tier becomes the bottleneck. Then, you scale up the SQL Server tier, and next scale it out by adding more MessageBox databases.


A new MessageBox database does not necessarily mean another server here. A single SQL server can have multiple MessageBox databases. Also, multiple MessageBox databases incur DTC cost and network hop if the databases are on different computers.

In theory, the SQL Server tier can scale out indefinitely as long as the master MessageBox database is not saturated.

The topics in this section describe these scaling patterns in more detail. They also explain how to scale each pattern and how to determine when you can no longer use that pattern to scale your system.

In This Section

See Also

Scaled-Out Receiving Hosts
Scaled-Out Processing Hosts
Scaled-Out Sending Hosts
Using Windows Server Cluster to Provide High Availability for BizTalk Server Hosts2
Scaled-Out Databases
Clustering the BizTalk Server Databases