[Linux-HA] 2 HA connections
aspanke at hpce.nec.com
Tue Aug 23 07:26:51 MDT 2005
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 ?
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
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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
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