I linked to the &quot;harder to grok&quot; piece because that&#x27;s what would give you programmatic control by setting an X header.  That&#x27;s as opposed to calling sendfile() yourself from your app.  Helpful if you&#x27;re trying to do something more than just serve up static files...like maybe in a page cache, where you also want dynamic control over other headers, etc.<p>The simpler sendfile=on would just be instructing nginx to use it for static files.