On Mon, 6 Jun 2005, Colm MacCarthaigh wrote:
> Yes, but it gets you very reliable L3 failover :) The end-result is
> the same.
Stuff like heartbeat fails across to /other/ machines. They're
complementary, i could imagine one using both heartbeat (to fail-over
between 2 machines) and bonding (to balance/failover between NICs on
> Although we use the bonding driver, we are not doing
> channel-bonding. Our aim is not to balance, but we do use it to
> team interfaces in order to have a resilient MAC, which can operate
> on either interface (but only one at a time). This is effectively
> exactly the same as the L3 failover, only a layer lower.
That'd work too. For one box.
> Our backup ports are on a different switch. You don't think we'd
> make our servers resilient and then plug them into one switch do
> you? ;) Our services network has multiple switches, as long as
> their in the same spanning-tree mesh, it works out fine :)
I'd be worried about odd artifacts though and/or hitting strange bugs
in switch firmware.
> There are other L3 failover options. Lately we're using OSPF as a
> L3 resilience mechanism to servers (Colin knows more about this),
> and it's working out quite well
Longer convergence time though with OSPF. Lowest you can set
dead-time is likely about 5s.
> (many thanks to your Quagga efforts).
And the other maintainers too.
> And for the next iteration of ftp.heanet.ie we're planning to
> distribute 4Gb/sec of connectivity via equal-cost static routes.
> So, if the network really is expensive and shiny, there's always
> those kinds of options also.
Many of these things are complementary, as I said above. You could
conceivably use all of bonding, IP failover and OSPF together. Each
one providing a slightly different part of the HA puzzle (OTOH, it
could be really fun to debug problems in such a case..).
Paul Jakma paul at clubi.iepaul at jakma.org Key ID: 64A2FF6A
He who is good for making excuses is seldom good for anything else.
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