[LinuxFailSafe] serial line for heartbeat

[Lars Marowsky-Bree]

On 2002-04-15T21:27:14,
   Marcus Doemling <marcus@fysix.com> said:

> It seems FailSafe requires 2 network cards just for the
> control network.

For redundancy, as Scott already said.

> It would be great to be able to use a serial connection
> for heartbeats and one ethernet connection. Like the
> "heartbeat" package does it. I'm sure it would be a popular
> option since it saves one network card.

I am not sure; network ports are cheap, as is the wiring. Serial ports aren't
even necessarily present in "recent" hardware...

> I spend a lot of time studing the guides for FailSafe but
> finally I have to go with "heartbeat" since I only have
> 2 network cards on each of my servers.

Well, the issue is that the FailSafe membership and group messaging protocol
is too high bandwidth for 38400 bps; it would actually adapt rather well to a
serial link ring, but I would suggest something like HIPPI or so ;-)

This is actually going to change with heartbeat too; I doubt that it will be
able to implement a real membership etc protocol over serial and achieve good
convergence times. The algorithms involved are a little bit more complex than
that.


Sincerely,
    Lars Marowsky-Brée <lmb@suse.de>

-- 
Immortality is an adequate definition of high availability for me.
	--- Gregory F. Pfister