When to use memory-mapped files?

Question

I have an application that receives chunks of data over the network, and writes these to disk. Once all chunks have been received, they can be decoded/recombined into the si

Answer 1

Memory-mapped files are primarily used for Inter-Process Communication or I/O performance improvement.

In your case, are you trying to get better I/O performance?

Hate to point out the obivious, but Wikipedia gives a good rundown of the situation... http://en.wikipedia.org/wiki/Memory-mapped_file

Specifically...

The memory mapped approach has its cost in minor page faults - when a block of data is loaded in page cache, but not yet mapped in to the process's virtual memory space. Depending on the circumstances, memory mapped file I/O can actually be substantially slower than standard file I/O.

It sounds like you're about to prematurely optimize for speed. Why not a regular file approach, and then refactor for MM files later if needed?