As a fun heuristic I have come to believe that mmap advocacy and use for storage is somewhat correlated with medium experience level.<p>At first junior developers don&#x27;t know about it, then, they read a blog, hear something at a meeting about it and all of the sudden they fall in love with mmap. Then they want to re-write every storage related thing using it claiming it will be lightning fast and efficient. &quot;You just write to memory and kernel writes to file, that so awesome, here I refactored your storage backend to use it over the weekend!&quot;<p>Some might even venture to write whole database products based on it.<p>But then one day they &quot;grow up&quot; and realize what a great pain mmap can be, their storage backend is being hammered constantly by input data and dirty pages are not flushed fast enough, and then they are they start blocking other processes for seconds at a time. THey start tweaking madvise setting trying to control behavior, adjusting number of pdflush threads, etc. Or, and also sigbus errors are fun...