First we need to configure the server:

• We assume that you already have a IIS server running.
• If you haven’t already, install PHP using these instructions
  • When you are editing the php.ini, enable the mysql, gd2, and mbstring extensions
• Install the Microsoft URL Rewrite Module
• Install the Fast-CGI admin panel (not required on IIS 7.5+)
• If you’re running on MySQL, you will need to download and install that too.

If you are using the SilverStripe development trunk and wish to use MS SQL server, you will need to perform the following additional server configuration:

• Install SQL Server client tools
• Install the SQL Server Driver for PHP 1.1, “sqlsrv”.
  • You will have to use the threadsafe version of the library (php_sqlsrv_ts.dll). On some configurations, PHP will just silently not load a non-threadsafe extension.
  • IMPORTANT: You should install a non-thread safe version of PHP AND a non-thread safe version of the SQL Server Driver for PHP 1.1 “sqlsrv”. VC9 of both is also preferred.

Then it’s time to install the SilverStripe installation package, and modify it to work with IIS:

• Download SilverStripe from http://www.silverstripe.com/silverstripe-web-application-framework/ and unpack it into your web-root, most likely c:\inetpub\wwwroot.
• Create a file called web.config in the silverstripe folder with the following content.

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
  <system.webServer>
    <rewrite>
      <rules>
        <rule name="SilverStripe Clean URLs" stopProcessing="true">
          <match url="^(.*)$" />
          <conditions>
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
          </conditions>
          <action type="Rewrite" url="sapphire/main.php?url={R:1}" appendQueryString="true" />
        </rule>
      </rules>
    </rewrite>
  </system.webServer>
</configuration>

• Visit the folder that you just extracted in your web browser. For example, the URL might be http://localhost/silverstripe-v2.3/. You will be shown the install screen.
• Enter your MySQL username and password in the boxes provided and press “re-check requirements”. You should be able to install now.
• After the installation has finished, delete the index.html and index.php files.
• You are encouraged to manually configure PHP to allow its mail() command to work, so that SilverStripe can send emails. This is used to email password reset, ecommerce checkouts, and other areas of the system.

Your site should be running at http://localhost/silverstripe-v2.3/

On high traffic sites you might find that you start getting “The FastCGI process exited unexpectedly” errors. This is related to PHP/IIS on FastCGI rather than anything SQL specific. There are plenty of resources on the internet if you Google “PHP The FastCGI process exited unexpectedly”.

To fix this, follow this guide on best practise setup for FastCGI applications on IIS.

IMPORTANT: You should ensure you are using the latest version of the sqlsrv driver. sqlsrv 1.1 is the latest, and works considerably better than 1.0. If possible, use PHP 5.3 as well.

You should ensure you are using the latest version of the sqlsrv driver. sqlsrv 1.1 is the latest, and works considerably better than 1.0 in terms of reliability and performance. If possible, use PHP 5.3 as well.

Try increasing the MaxInstances from 4 to a higher value. For quad core CPUs, a higher value such as 32 should prove to provide a performance enhancement.

You can also install wincache for IIS, to improve performance on live sites.

You can also try installing and enabling static and dynamic content compression for IIS on live sites.

Doing all of the above should provide a significant performance boost to your site.

• Follow the instructions above, but note differences:
• You cannot install the URL Rewriter shown above, because Microsoft has no such plugin for those IIS older versions. This will mean your URLs are like yoursite.com/index.php/about-us rather than yoursite.com/about-us. If you do want friendly URLs you must you must buy or use other URL rewriting software
  • ISAPI_Rewrite: http://www.helicontech.com/download-isapi_rewrite3.htm
    • (The freeware, lite version should be fine for simple installations.)
  • If you have 64-bit windows, you can try this one:
    • http://www.micronovae.com/ModRewrite/ModRewrite.html
• Instructions for installing PHP IIS 5.1 and 6 may be different that for 7. See http://learn.iis.net/page.aspx/248/configuring-fastcgi-extension-for-iis60/
• On XP, you need to disable ‘Check that file exists’ (See installation-on-windows-pi)

Matthew Poole has expanded on these instructions with this tutorial: http://cubiksoundz.blogspot.com/2008/12/tech-note-installing-silverstripe-cms.html