[ayende]

The key from my perspective is that I CAN design my access patterns to match what you'll optimized.

Another aspect to remember is that mmap being even possible for databases as the primary mechanism is quite new.

Go 15 years ago and you are in 32 bit land. That rule out mmap as your approach.

At this point, I might as well skip the OS and go direct IO.

As for differ OS behavior, I generally find that they all roughly optimize for the same thing.

I need best perf on Linux and Windows. Other systems I can get away with just being pretty good