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Thread: Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

Last post 10-02-2009 8:38 PM by lextm. 6 replies.

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  • 09-30-2009, 4:52 PM

    Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

    I have a Load Balanced web farm with 3 web servers which server web services to a WinForms desktop app. If I set HTTP Keep-Alives Enabled = True, general speed of performance is much better but I get many of these errors: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server. If I set HTTP Keep-Alives Enabled = False, the errors all but disappear, but the speed of the app lags. Does anyone have a solution for keeping the speed of Keep-Alives but not the errors on a Load Balanced farm? Regards, Eric Bechtinger
  • 10-01-2009, 12:11 AM In reply to

    • lextm
    • Top 10 Contributor
    • Joined on 10-22-2008, 4:18 AM
    • Shanghai, PRC
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    Re: Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

    Do you use a load balancer or Windows Load Balancing Service?

    Lex Li
    Support Engineer at Microsoft
    ---------------------------
    This posting is provided "AS IS" with no warranties, and confers no rights.
  • 10-01-2009, 3:23 AM In reply to

    Re: Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

    What's your sever model? I have one experienced in the past that it has something to do with network card setting - receive side scaling - set to disable.

    HTTP keep alive is client will maintain the same connection when IIS response rather than open up a new one each time. Generally, you should keep it alive.

    Anyway, how do you load balance your web farm?

    Cheers,
    Bernard Cheah
  • 10-01-2009, 9:52 AM In reply to

    Re: Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

    Thanks for working we me on this. We use a Cisco CSS load balancer.
  • 10-01-2009, 8:04 PM In reply to

    • lextm
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    • Joined on 10-22-2008, 4:18 AM
    • Shanghai, PRC
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    Re: Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

    Eric, as the TCP connection was reset (HTTP is built on TCP) and led to the error message you saw in the WinForms application, it is necessary for us to track down who reset the connection and then apply necessary actions.

    Generally speaking, this is not an easy task as it requires both IIS and networking knowledge and it requires a lot of efforts. I can only provide you some hints here and if you like you can open a support case via http://support.microsoft.com

    1. Start to capture Microsoft Network Monitor logs from both the WinForms machine and all the IIS 5 servers at the same time.

    2. Reproduce this error message.

    3. Stop captures and analyze the logs to locate the TCP reset packet.

    4. Find out who reset the connection

    That's only the first step. Once the guilty is found, it is possible to move and apply further actions.

    Lex Li
    Support Engineer at Microsoft
    ---------------------------
    This posting is provided "AS IS" with no warranties, and confers no rights.
  • 10-02-2009, 5:07 PM In reply to

    Re: Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

    How do I get the Microsoft Network Monitor logs on the WinForms machine and all the IIS 5 servers?

    Is this built in to IIS and the OS or do I need another tool that you recommend?

    Thanks again.

  • 10-02-2009, 8:38 PM In reply to

    • lextm
    • Top 10 Contributor
    • Joined on 10-22-2008, 4:18 AM
    • Shanghai, PRC
    • Posts 1,413

    Re: Load Balanced IIS 5 and the HTTP Keep-Alives Enabled setting

    We have a download version here for Windows XP and upper, so if your WinForms applications run on them you can use it.

    http://www.microsoft.com/downloads/details.aspx?FamilyID=983b941d-06cb-4658-b7f6-3088333d062f&displaylang=en

    But since you are still using Windows 2000/IIS 5, on those servers you need to enable Network Monitor from Control Panel | Programs | Install Windows components, as this 3.3 release won't work on that old Windows. Note that once captured in this old netmon, the capture files can be opened and analyzed in 3.3.

    Lex Li
    Support Engineer at Microsoft
    ---------------------------
    This posting is provided "AS IS" with no warranties, and confers no rights.
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