Considerations While Using BizTalk Server on a 64-bit Windows Operating System

When using BizTalk Server on a 64-bit Windows operating system, make sure you consider the issues described in this topic. For frequently asked questions related to 64-bit support for Microsoft BizTalk Server 2009, see BizTalk Server 64-bit Support ( in BizTalk Server 2009 Help.

The default memory dehydration thresholds may cause excessive dehydration when running orchestrations on a 64-bit host. This can cause a significant decrease in performance. Because 64-bit architecture provides expanded memory address space (8 TB instead of 4 GB), 64-bit host instances are allocated significantly more memory than 32-bit host instances. This can cause the default memory throttling thresholds to be exceeded. For more information about dehydration properties, see Dehydration Default Properties (

To work around this behavior, change the VirtualMemoryThrottlingCriteria and PrivateMemoryThrottlingCriteria values in the BTSNTSvc64.exe.config file. Use the Process\Virtual Bytes and the Process\Private Bytes Performance Monitor counters to determine the largest amount of memory that is being allocated by a host instance hosting orchestrations.

  • Set the OptimalUsage value for both properties based on the following:

    • VirtualMemoryThrottlingCriteria = \Process\Virtual Bytes value + 10%

    • PrivateMemoryThrottlingCriteria = \Process\Private Bytes value + 10%

  • Set MaximalUsage for both properties to OptimalUsage value + 30%

For example, if the \Process\Virtual Bytes Performance Monitor counter value for a host instance hosting orchestrations is 5,784,787,695 bytes (5,517 MB), set the OptimalUsage value for VirtualMemoryThrottlingCriteria to 6,069 MB (5,784,787,695 * 1.10 = 6,363,266,464.5 bytes). Similarly, set the MaximalUsage value for VirtualMemoryThrottlingCriteria to 7,889 MB (6,363,266,464.5 * 1.30 = 8,272,246,403.85 bytes).

If the \Process\Private Bytes Performance Monitor counter value is 435689400 bytes (415 MB), set the OptimalUsage value for PrivateMemoryThrottlingCriteria to 457 MB (435689400 * 1.10 = 479258340 bytes). Set the MaximalUsage value for PrivateMemoryThrottlingCriteria to 594 MB (479258340 * 1.30 = 623035842).

To summarize, for this example, the following values would be specified in the BTSNTSvc64.exe.config file to reduce throttling.

Performance Monitor counter Memory allocated OptimalUsage MaximalUsage

\Process\Virtual Bytes

5784787695 bytes (5517 MB)



\Process\Private Bytes

435689400 bytes (415 MB)



In the BTSNTSvc64.exe.config, these values will be represented as:

      <VirtualMemoryThrottlingCriteria OptimalUsage="6069" MaximalUsage="7889" IsActive="true" />
      <PrivateMemoryThrottlingCriteria OptimalUsage="457" MaximalUsage="594" IsActive="true" />

By default, the Process memory usage host throttling threshold is set to 25. If this value is exceeded and the BizTalk process memory usage is more than 300 MB, a throttling condition may occur. On a 64-bit server, you can increase this value to 100. This allows for more memory consumption by the BizTalk process before throttling occurs. For instructions on how to modify the process memory usage host throttling threshold, see How to Modify the Default Host Throttling Settings (

The following adapters are not supported to run on 64-bit host instances:

  • FTP adapter

  • POP3 adapter

  • SQL adapter

Make sure you run these adapters in a 32-bit host instance.

The WCF-based Microsoft BizTalk Adapter for Siebel eBusiness Applications, bundled with the Microsoft BizTalk Adapter Pack, is not supported on a 64-bit Windows Operating System because the Siebel client (required by the Siebel adapter to interface with the Siebel system) is not available for 64-bit operating system.

In BizTalk Server 2009, the MIME/SMIME encoder pipeline component dies not have native 64-bit support. This means that this component must be run in a 32-bit emulation mode process (WOW64). This implies that the host instance in which this encoder component (or the send pipeline of which it is a part) runs must be running in 32-bit emulation mode. Be aware of the performance (and other) implications of this restriction for other elements of BizTalk running in this same host instance.