Willy, > You're perfectly right, redispatch only happens when the > request is still > in haproxy. Once it has been sent, it is cannot be performed. > It must not > be performed either for non idempotent requests, because > there is no way > to know whether some processing has begun on the server before it died > and returned an RST.
I suspected that this would be the case. > > > Any further advice would be much appreciated, I can provide packet > > captures off list if required. > > Shouldn't you include the Host header in the health checks, > in order to > sollicit the final server and get a chance to see it fail ? The health checks naturally include the Host header, and work properly. We just wanted to avoid returning 503 to the client for the 4-14 seconds it takes for the backend server to be reported down (inter 5 fall 2). We'll see if there's something we can do to get IIS to return a RST before it receives the full request. -JohnF
