XCON: MTA Logs Warning Events When Queues Reach Specified Sizes

ID: Q163085

The information in this article applies to:

Microsoft Exchange Server, version 5.0 Service Pack 2

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

SUMMARY

The Microsoft Exchange message transfer agent (MTA) versions 1459.39 and later allow Exchange administrators to configure queue thresholds that cause the MTA to log warnings in the application event log when the specified queue size has been exceeded.

This feature is included in the latest Microsoft Exchange Server version 5.0 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

MORE INFORMATION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

There are four new registry settings that can be used to configure these warning events to be logged:

Work queue alarm on
Work queue alarm off
Outbound queue alarm on
Outbound queue alarm off

All four of these case-sensitive registry values are REG_DWORDs and can be added to the following registry key:


   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services
   \MSExchangeMTA\Parameters

To create one of these registry values, follow the example below for configuring the Work queue alarm:

Start Registry Editor (Regedt32.exe) and go to the following sub-key:
```
      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
      \MSExchangeMTA\Parameters 
```
NOTE: The above registry key is one path; it has been wrapped for readability.

Click Add Value on the Edit menu.

Enter the following in the Value Name field:
Work queue alarm on

In the Data Type list, click REG_DWORD.

Click OK.

Click Decimal option, and then enter the number of messages that must be queued in the Work queue for the Work queue alarm to be triggered.

The work queue alarm may log two different events to notify the administrator when the work queue reaches a certain size. One event notifies the administrator that the work queue has reached the "alarm on" threshold. This warning is logged with the event ID 666 and looks similar to the following:


   Event ID:666
   Source:MSExchangeMTA
   Type:Warning
   Category:Resource
   Description:
   The MTA work queue is backlogged with 600 messages in
   the queue. [MTA SUBMIT 18 231] (14)

After the work queue diminishes in size, the MTA will log a warning with the event ID 667 that looks similar to the following:


   Event ID:667
   Source:MSExchangeMTA
   Type:Warning
   Category:Resource
   Description:
   The MTA work queue backlog has subsided leaving 300 messages in
   the queue. [MTA DISP:RESULT 23 234] (14)

The work queue alarm can be configured by using only the "Work queue alarm on" registry value. When the "Work queue alarm off" registry value is not present, the MTA will automatically substitute half the value specified in the "Work queue alarm on" registry value for the "off" value, which uses the 667 event to be triggered. The example events shown above illustrate this configuration, where the "Work queue alarm off" value is not present in the registry and the "Work queue alarm on" registry value has been set to 600 decimal.

The "Work queue alarm off" registry value can be configured to log the 667 event at a different value if the administrator wants. For example, if the "Work queue alarm off" registry value is set to a value of 0, the 667 event will not be logged until the work queue has been emptied completely. Another example would be to set the "Work queue alarm off" value to 100 decimal, which would result in the 667 event being logged when the work queue diminishes to 100 messages. If the "Work queue alarm off" value is set to a higher value than the "Work queue alarm on" value, the value specified for "Work queue alarm off" will be ignored, and the default value of half the "Work queue alarm on" value will be used instead.

The "Outbound queue alarm on" and "Outbound queue alarm off" registry values work similarly to the work queue alarm settings. The outbound queue alarm works independently from the work queue alarm. The outbound queue alarm logs a 659 event ID when a queue reaches the specified limit. For example, if the "Outbound queue alarm on" registry value is configured to generate the 659 event when an outbound queue reaches 500 messages and an X.400 connector becomes backlogged to 500 messages or more, an event similar to the following will be logged in the application event log:


   Event ID:659
   Source:MSExchangeMTA
   Type:Warning
   Category:Resource
   Description:
   The queue for /O=MS/OU=GUITARS/CN=CONFIGURATION
   /CN=CONNECTIONS/CN=X400 CONNECTOR TO BRASS_KITTEN
   is backlogged with 500 messages in the queue.
   [MTA GATEWAY 45 512] (14)

When the backlog subsides, a 660 event similar to the following will be logged:


   Event ID:660
   Source:MSExchangeMTA
   Type:Warning
   Category:Resource
   Description:
   The queue backlog for /O=MICROSOFT/OU=GUITARS
   /CN=CONFIGURATION/CN=CONNECTIONS/CN=X400 CONNECTOR TO
   BRASS_KITTEN has subsided leaving 250 messages in the
   queue. [MTA GATEWAY 45 512] (14)

The functionality described above is available in version 1459.39 or later of the MTA.

Keywords : kbusage kbfix5.00.sp2 XCON
Version : WinNT:5.0
Platform : winnt
Issue type : kbinfo