There is a note at https://www.varnish-cache.org/docs/3.0/reference/vcl.html that says
bereq.first_byte_timeout
The time in seconds to wait for the first byte from the backend. Not available in pipe mode.
Does this mean that the first_byte_timeout is ignored for all piped requests to the backend?
That is correct.
As the documentation states about
pipe
:You won't even see the
X-Varnish
-headers appear in piped requests.