Re: TCP traffic multiplexing as balance algorithm?

Hi,

Willy Tarreau <w#1wt.eu> wrote:
> Hi Maik,
>
> On Tue, May 12, 2009 at 01:57:47AM +0200, Maik Broemme wrote:
> > Hi,
> >
> > I have a small question. Did someone know if it is possible to do simple
> > traffic multiplexing with HAProxy? Maybe I am missing it somehow, but
> > want to ask on the list before creating a patch for it.
>
> what do you call "traffic multiplexing" ? From your description below, I
> failed to understand what it consists in.
>

Multiplex means traffic duplication. If you have multiple server configuration options in one listen group, the incoming traffic is sent to all servers.

> > Just to answer the real-world scenario question. TCP multiplexing can be
> > very useful for debugging backend servers or doing a simple logging and
> > passive traffic dumping.
> >
> > There are two major ideas of implementing it:
> >
> > - 1:N (Active / Passive)
> > - 1:N (Active / Active)
> >
> > Well active means that request is going to destination and response back
> > to client and passive means that only request is going to the destination.
> > In configuration it could look like:
> >
> > listen smtp-filter 127.0.0.1:25
> > mode tcp
> > balance multiplex
> > server smtp1 10.0.0.5:25
> > server smtp2 10.0.0.6:25
> >
> > The active / active would be very hard to implement, tcp stream
> > synchronisation would be a pain and I think no one will really need
> > this, but active / passive is a very useful feature.
> >
> > In my environment it is often so, that developers need access to real
> > traffic data to debug (in the example above) their developed smtp
> > software. Is anyone else missing such functionality? :)
>
> Access to real data is solved with tcpdump or logs, I don't see what
> your load-balancing method will bring here.
>

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.

> > --Maik
>
> Regards,
> Willy
>

--Maik Received on 2009/05/13 10:40