Some of our findings were that there were no significant differences in database performance based on OS. By far, the largest factors affecting performance were hardware (CPU, disk, RAM), network (NIC, Fibre Channel cards, switches), and database configuration.

We have had fewer security problems with our Windows servers than with our Linux servers. However, that may be different in other organizations. My feeling is that any OS can be secure if configured properly.

Our conclusion was that the best OS to choose was the one for which you have the most in-house expertise and resources.