Re: TCP traffic multiplexing as balance algorithm?

Maik Broemme a écrit :
> Hi,
>
>
> Multiplex means traffic duplication. If you have multiple server
> configuration options in one listen group, the incoming traffic is
> sent to all servers.
>

Hum, i'm sorry but no, multiplexing is not duplication. In fact it's more like the opposite,
it's the process of combining multiple data stream into one (long descr. here: http://en.wikipedia.org/wiki/Multiplexing)
>
> tcpdump is not perfect in that case, because it has to run the hole time
> you want to duplicate the traffic and sent it to server1 and server2.
>

So let's say you pacth haproxy and he duplicate traffic to two servers and is able to forget
data from one (the dev/test one) and keep the other (the prod one).

How will haproxy been able to react to the different responses/timing from each servers ?
Let's say you duplicate MX traffic, with the test server being used to validate a new configuration
to keep away spammers (simple example).
Let's say both server are able to answer at the exact same time or aren't too frisky about having the answer before the question, when the prod server will accept the mail message and start listinening from it's main
part the other could have rejected it, however he still will receive the main part, while not expecting it,
which depending of the implementation could lead to troubles, like if the originating mail server try to
 send another mail using the same connection.

This is a very simple example and most MX implementation could react correctly but that's not the case of
everything Received on 2009/05/13 12:38