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Q163085: XCON: MTA Logs Warning Events When Queues Reach Specified Sizes

Article: Q163085
Product(s): Microsoft Exchange
Version(s): winnt:5.0 SP2,5.5
Operating System(s): 
Keyword(s): kbusage exc55 exc5sp2
Last Modified: 11-JUN-2002

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The information in this article applies to:

- Microsoft Exchange Server, versions 5.0 SP2, 5.5 
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IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

  Q256986 Description of the Microsoft Windows Registry

SUMMARY
=======

The Microsoft Exchange Server message transfer agent (MTA) versions 1459.39 and
later allow Exchange Server 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: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.

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:

1. 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.

2. Click Add Value on the Edit menu.

3. Enter the following in the Value Name field:

  "Work queue alarm on" (without the quotation marks)

4. In the Data Type list, click REG_DWORD.

5. Click OK.

6. 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.


Additional query words:

======================================================================
Keywords          : kbusage exc55 exc5sp2 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2 kbExchange500SP2
Version           : winnt:5.0 SP2,5.5
Issue type        : kbinfo

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