Factors that help:
- Stability
- Source availability for helping understand and fix
problems that occur (having the source to the
system helps you understand why your application does not
do what you expect)
- Good performance
- Easy hardware upgrade paths
- The application is spread over many servers.
Need more power in one part? Add more FreeBSD boxes.
PC hardware sometimes is less than perfect, but at PC
hardware prices, hot spares are practical.