Interesting line of reasoning. Definitely mmaping 8.6TiB into user space process virtual memory is gonna take a toll.<p>I tried to find why varnish doesn&#x27;t use sendfile:
 <a href="https:&#x2F;&#x2F;www.varnish-cache.org&#x2F;lists&#x2F;pipermail&#x2F;varnish-dev&#x2F;2008-May&#x2F;005891.html" rel="nofollow">https:&#x2F;&#x2F;www.varnish-cache.org&#x2F;lists&#x2F;pipermail&#x2F;varnish-dev&#x2F;20...</a><p><pre><code>  By default [Varnish uses sendfile] never; there are problems with all sendfile() implementations</code></pre>