Approach used to convert the Hotmail web server farm from Unix to Windows (2002)

Microsoft's conversion of Hotmail's web server farm from UNIX to Windows 2000 is detailed in a white paper that outlines the project's rationale, methodologies, and early results. The conversion aimed to improve hardware utilization, leverage superior development tools, and serve as a model for future UNIX transitions. Initial findings indicate that Windows 2000 offers better throughput and performance compared to UNIX, although the administrative model of Windows is less suited for such conversions. The project faced constraints typical of large Internet sites, including the need for continuous service and adherence to an eight-week upgrade cycle.

Hotmail's architecture, originally built on UNIX systems, included front-end web servers running Apache on FreeBSD and back-end file stores on Solaris. The conversion focused on front-end servers, which are critical for user interaction. Key features of Hotmail's operation included the need for 100% availability, simultaneous upgrades, and a controlled environment for administration. The paper emphasizes the importance of maintaining identical configurations across thousands of servers to streamline management and ensure stability.

The advantages of UNIX, such as familiarity and stability, are acknowledged, but the transition to Windows is seen as necessary for future growth and development. The paper concludes that while the conversion is ongoing, the insights gained will inform similar projects and enhance the overall performance and reliability of Hotmail's services.