[Linux-HA] 2 HA connections

[Alexander Spanke]

Hi all,

OK, I understand your arguments and I agree with them, so but that makes my life
a bot more complicated :(

The NFS servers described in the active/passive configuration are 1U 19"
machines, which are limited in space. The HA connection between them is a
seperate network interface connected via a crosscable. If I would go the step
to have a redundant HA connection, I only have the chance of using USB, because
the serial connector is occupied by a external TerminalServer.

Is it possible to use USB for a HA - connection ?

Thnx
 Alex

Zitat von Alan Robertson <alanr at unix.sh>:

> Alexander Spanke wrote:
> > Hi all,
> >
> > I am just evaluating the question if a second HA connection is needed or
> > not on our cluster.
> >
> > The environment is as following, I have 2 NFS Server in active/passive
> > configuration. Both server are monitoring themself using the
> > 'ping_group' directive and 1 HA connection between them to monitor each
> > other.
> >
> > Now I got the question if we should activate a 2nd HA connection. I
> > think this is not needed, because the systems are monitoring themself
> > anyway and are getting monitored by the other machine. I only can
> > imagine to avoid 1 failover, in case of broken HA cable, with using a
> > second HA connection.
> >
> > Am I right so far ? Or what do you think ?
>
>
> We always recommend redundant connections.
>
> The servers should not give each other's addresses in ping, if that's
> what you're saying.
>
> The purpose of the second connection is to provide redundancy - which
> will prevent split-brain - which is something to be avoided.
>
> Without redundancy, the software can't recover from errors (like loss of
> the HA comm link).  In this case, the inability to recover is more
> problematic - because of the split-brain issue.
>
>
> --
>      Alan Robertson <alanr at unix.sh>
>
> "Openness is the foundation and preservative of friendship...  Let me
> claim from you at all times your undisguised opinions." - William
> Wilberforce
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>
>


--
=======================================================
Alexander Spanke                         System Analyst
      NEC High Performance Computing Europe GmbH
Prinzenallee 11            D-40549 Duesseldorf, Germany
Tel:    +49 211 5369 146           aspanke at hpce.nec.com
Fax:    +49 211 5369 199        http://www.hpce.nec.com
=======================================================