Major revision of FastCGI/PHP article on IIS.NET

Since the time we have published the article about installing FastCGI and PHP on IIS 7.0 it has become one of the most popular articles on Also it has received a lot of comments from site visitors. Today, we are publishing the updated version of this article that contains more up-to-date information and addresses most of the feedback from community. Here is what this article includes now:

Please take a look at the new content and leave comments if you have any questions of feedback.

Acknowledgments: I would like to thank IIS.NET visitors who have provided their comments and corrections to this article. Also I thank Jake and Bill for doing a final review of the article.


ruslany on October 31st 2008 in FastCGI, PHP

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6 Responses to “Major revision of FastCGI/PHP article on IIS.NET”

  1. Gravatar ImageFranklin Tse responded on 31 Oct 2008 at 8:09 pm #


    I noticed that the default parameter values of the IIS 7.0 FastCGI Module is different from those in the FastCGI Extension for IIS 6.0. Is there any reason for that?

    (Also posted at

  2. Gravatar ImageFranklin Tse responded on 31 Oct 2008 at 8:22 pm #

    Oops… I forgot to mention that the non-thread-safe installer on can be used after PHP 5.2.7, which is currently in RC stage, is released. That’s because the issue documented in has been fixed.

    The installer can install the php-cgi.exe (with Other CGI selected) and allow users to install PHP extensions without any manual modification.

    The RC of the installer can be found on

  3. Gravatar Imageruslany responded on 03 Nov 2008 at 11:25 am #

    In our tests we saw that increasing the InstanceMaxRequests improved the performance of FastCGI with PHP slightly. However, if this setting is configured to a value bigger than 500 (PHP’s default for process recycling), then it may conflict with PHP recycling behavior (as described Since the performance difference between InstanceMaxRequests set to 200 vs. 1000 was not significant, but the chances of getting server errors with default value set to 1000 were higher, it was decided to change the default to 200. However it was too late to change it for IIS 6, as the FastCGI extension was about to be shipped then.

  4. Gravatar ImageFranklin Tse responded on 04 Nov 2008 at 7:13 pm #

    Thanks! However, besides the InstanceMaxRequests, the MaxInstances default has also been changed from 10 to 4. Is 4 better than 10?

  5. Gravatar Imageruslany responded on 05 Nov 2008 at 11:28 pm #

    For MaxInstances there is no technical reason for the difference in defaults. One value is not better than the other. For development purposes either of the defaults would work fine. For production deployment you would probably need to fine tune this number anyway to achieve full CPU load.

  6. Gravatar ImageRuslanY Blog responded on 20 Feb 2009 at 8:37 pm #

    Windows Installer for PHP 5.2.9 RC and PHP 5.3 Beta…

    I am pleased to let everyone know that PHP development community has made significant improvements to the installer in upcoming PHP releases. In particular a number of bugs have been fixed to make the installer work well with FastCGI extension in IIS 5…

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