KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q139212: Memory Leak in TN3270 Server if RU Sizes Exceed TN3270 Defaults

Article: Q139212
Product(s): Microsoft SNA Server
Version(s): WINDOWS:2.11
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 13-JUN-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft SNA Server, version 2.11, on platform(s):
   - the operating system: Microsoft Windows NT 
-------------------------------------------------------------------------------


SYMPTOMS
========

When the TN3270 server runs for many days or weeks, server performance becomes
sluggish and Windows NT eventually runs out of virtual memory. Also, Windows NT
performance monitor shows paged pool bytes to be steadily increasing for the
TN3SERVR process.

CAUSE
=====

The TN3270 server initially allocates inbound and outbound buffers when a TN3270
client connects to the server, using the inbound and outbound "Default RU sizes"
configured in the TN3270 Admin Options dialog.

However, if the TN3270 client's BIND request negotiates to larger RU sizes than
these defaults, the TN3270 server allocates new inbound and outbound buffers
though never frees the previously acquired buffers.


RESOLUTION
==========

To workaround this problem, increase the Inbound and/or Outbound default RU
sizes within the TN3270 Server Admin Options dialog to accommodate the largest
RU sizes that will be requested by the TN3270 client users.

To correct this problem, install the update to the SNA Server 2.11 TN3270 service
mentioned below. Microsoft has updated the file <ntroot>\TN3SERVR.EXE to
correct this problem.


STATUS
======

Microsoft has confirmed this to be a problem in SNA Server for Windows NT. This
problem was corrected in the latest SNA Server for Windows NT, 2.11 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

Additional query words: prodsna 3.50 3.51

======================================================================
Keywords          : kbnetwork 
Technology        : kbAudDeveloper kbSNAServSearch
Version           : WINDOWS:2.11
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.