DOCUMENT:Q174644 12-JUN-2001 [sna] TITLE :Perfmon Degrades SNA Server When Many 3270 LUs in Use PRODUCT :Microsoft SNA Server PROD/VER:winnt:2.11 (all SP),3.0 (all SP),4.0 OPER/SYS: KEYWORDS:kbnetwork ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft SNA Server for Windows NT, versions 2.11 SP1, 2.11 SP2, 3.0 SP1, 3.0 SP2, 3.0 SP3, 3.0 SP4, 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When you use Windows NT Performance Monitor to monitor any SNA performance objects every second, SNA Server performance degrades significantly when 150 users or more have an active 3270 session. Users with active 3270 sessions receive host response delays from 20 seconds to two minutes. CAUSE ===== When you monitor SNA Server performance objects, SNA Server reports response time monitor (RTM) performance data on every active 3270 LU. When a large number of 3270 LUs are in use, this reporting can degrade 3270 performance for current 3270 users if a small Performance Monitor reporting interval is chosen (such as the default one-second reporting interval in Windows NT Performance Monitor). RESOLUTION ========== To prevent the problem from occurring with SNA Server 2.11 or 3.0, follow these steps: 1. Choose an infrequent Performance Monitor reporting interval, such as one minute or more, rather than the default of one second. 2. Do not continuously monitor SNA Server performance objects during production use STATUS ====== Microsoft has confirmed this behavior with SNA Server versions 2.11, 3.0, and 4.0 and is investigating how to address this issue in future releases. This problem was corrected in the latest SNA Server version 4.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces): S E R V P A C K The updated SNA Server 4.0 modules are: \system\snaservr.exe \system\trcservr.exe \system\snaperf.dll MORE INFORMATION ================ For additional information about another possible performance problem, please see the following article in the Microsoft Knowledge Base: Q168717 SNA Server Performance Degrades If Domain Controller Down Additional query words: ====================================================================== Keywords : kbnetwork Technology : kbAudDeveloper kbSNAServSearch kbSNAServ400NT kbSNAServ211NTSP1 kbSNAServ211NTSP2 Version : winnt:2.11 (all SP),3.0 (all SP),4.0 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. Copyright Microsoft Corporation 2001.