O verniz será bom para o trabalho:
sub vcl_backend_response {
# ...
# Large static files are delivered directly to the end-user without
# waiting for Varnish to fully read the file first.
# Varnish 4 fully supports Streaming, so use streaming here to avoid locking.
if (bereq.url ~ "^[^?]*\.(mp[34]|rar|rpm|tar|tgz|gz|wav|zip|bz2|xz|7z|avi|mov|ogm|mpe?g|mk[av]|webm)(\?.*)?$") {
unset beresp.http.set-cookie;
set beresp.do_stream = true;
set beresp.do_gzip = false; # Don't try to compress it for storage
}
# ...
}