MTA Transfer threads parameter is non-default

Topic Last Modified: 2007-11-14

The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine its current value:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeMTA\Parameters\Transfer threads

If the Exchange Server Analyzer finds the value for Transfer threads present and greater than 0 but set to anything other than 1 or 2, a non-default configuration message is displayed.

The Transfer threads value is the number of message transfer agent (MTA) Transfer threads. This is multiplied by two for the two subtypes (Transfer In and Transfer Out) of each Transfer thread. This is the equivalent of the Submit/deliver threads value (which relates to MTA and information store message transfer) but for gateways and MTAs. For more information about the Submit/deliver threads value, see MTA Submit/deliver threads parameter is non-default.

If this is an Exchange 2000 Server or Exchange Server 2003 MTA that communicates with more than one Exchange Server version 5.5 computer either within a site or between sites, it is recommended that you adjust the value for Transfer threads to 3.

On some Exchange Server 5.5 computers, it is possible that this value was automatically changed by the Exchange Performance Optimizer from its default value of 2 to a value more appropriate for the Exchange Server computer.

Important:
This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.

To configure the Transfer threads value

Open a registry editor, such as Regedit.exe or Regedt32.exe.
Navigate to: HKLM\System\CurrentControlSet\Services\MSExchangeMTA\Parameters
In the right pane, locate and double-click the Transfer threads value.
In the Value data field, enter the appropriate value and click OK.
Close the registry editor and restart the Microsoft Exchange MTA Stacks service for the change to take effect.

On Exchange 2000 Server and Exchange Server 2003 computers, the value for this entry should be set no greater than 3. As an alternative to the preceding procedure, you can run the Exchange Performance Optimizer in verbose mode (perfwiz.exe -v) and set the value using that tool.

Before you edit the registry, and for information about how to edit the registry, read the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=256986).

For more information about situations in which the MTA Transfer threads registry value should be altered from its default value, see the following Knowledge Base articles:

234280, "XCON: How to Increase the Ability of the MTA to Pass Mail over Slow Network Connections" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=234280)
265186, "XCON: MTA Fanout Slows on Multiprocessor Servers and Messages Back Up in Information Store" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=265186)
327260, "MTA slows down or stalls in Exchange Server 5.5 and messages back up in the private information store" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=327260)