Perlbal has a nice feature called verify_backend that what it does is
send an OPTIONS request each time a new connection to a backend is
made to ensure that it has the backend’s atention.
With persistent backend connections this makes more sense since the
overhead is minimized but, even so, I think it’s an interesting
feature since apache tends to keep clients waiting when MaxClients is
reached. We can lower ListenBacklog but still some clients get stuck
after the connection is accepted.
proxy_read_timeout is not very useful here since specifying a
different timeout for each type of request being made can quickly get
out of hand… We just want to be sure that apache is processing the
I think this would be a useful feature for nginx.