Reliability FreeBSD is extremely robust. There are numerous testimonials of active servers with uptimes measured in years. The new Soft Updates1 file system optimizes disk I/O for high performance, yet still ensures reliability for transaction based applications, such as databases. Linux is well known for its reliability. Servers often stay up for years. However, disk I/O is non-synchronous by default, which is less reliable for transaction based operations, and can produce a corrupted filesystem after a system crash or power failure. But for the average user, Linux is a very dependable OS. All Windows users are familiar with the "Blue Screen of Death". Poor reliability is one of the major drawbacks of Windows. Some of the major issues have been fixed in Windows 2000, but "code bloat" has introduced many more reliability problems. Windows 2000 uses a lot of system resources and it is very difficult to keep the system up for more than a couple of months without it reverting to a crawl as memory gets corrupted and filesystems fragmented.
Performance FreeBSD is the system of choice for high performance network applications. FreeBSD will outperform other systems when running on equivalent hardware. The largest and busiest public server on the Internet, at ftp.freesoftware.com, uses FreeBSD to serve more than 1.2TB/day of downloads. FreeBSD is used by Yahoo!, Qwest and many others as their main server OS because of its ability to handle heavy network traffic with high performance and rock solid reliability. Linux performs well for most applications, however the performance is not optimal under heavy network load. The network performance of Linux is 20-30% below the capacity of FreeBSD running on the same hardware 2. The situation has improved somewhat recently and the 2.4 release of the Linux kernel will introduce a new virutual memory system based on the same concepts as the FreeBSD VM system.