[Pacemaker] Pacemaker cluster: OpenAis communication channels

[Romain CHANU]

Florian, I have checked the different links you have sent and I am a bit
confused with this RRP matter.

I want to use two machines (primary / secondary) and set up the following
interfaces:

- eth0 : direct link between primary and secondary
- bond0: bonding of eth1 and eth2 (redundant network with two switches).

Will there be any issues while using these two interfaces for OpenAis
communication channels? (especially with the bonding)

Thank you.

2009/10/22 Florian Haas <florian.haas at linbit.com>

> Steve,
>
> what has repeatedly come up is that RRP links don't auto-heal (see
> thread:
> http://oss.clusterlabs.org/pipermail/pacemaker/2009-May/001784.html),
> and that passive mode RRP seems to not work at all (see thread:
>
> https://lists.linux-foundation.org/pipermail/openais/2009-October/013095.html
> -- this was also heavily discussed on IRC; the only approach that fixed
> the issue was to change rrp_mode to active). Can you fill us in on the
> progress on these issues? Thanks!
>
> Cheers,
> Florian
>
> On 10/22/2009 06:14 AM, Steven Dake wrote:
> > You can run with one NIC (and switch) but then your NIC and switch
> > become a SPOF (single point of failure).  Vehicles have a spare tire for
> > a reason :)  If a NIC fails it may be ok to switch a service to a
> > different node.  If a switch fails, The entire cluster becomes disabled
> > until the switch returns to operation.
> >
> > Availability is a mathematical equation:
> >
> > A = MTTF / (MTTF+MTTR)
> >
> > Pacemaker improves availability (A) by reducing mean time to repair
> > (MTTR) using failover while keeping the mean time to failure (MTTF)
> > essentially the same (although it is generally a bit lower because of
> > other components in the system required to introduce redundancy).
> > Instead of a typical 1 machine MTTR of 4 hours under a typical SLA, MTTR
> > may be 5-10 seconds or less (the time to failover the application and
> > restart it).  If MTTR is several days to service a switch, your
> > availability may not meet your customer SLA obligations.  When
> > determining whether to use a redundant switch the risks vs cost have to
> > be evaluated based upon your availability requirements.
> >
> > Regards
> > -steve
>
>
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