[Linux-HA] heartbeat over ethernet with ipfail question

R.Schramp at telecom.tno.nl R.Schramp at telecom.tno.nl
Tue Mar 15 08:41:37 MST 2005

Hello Matt,

this is exactly how I understood it from the manual,
however I see not so much point in failing over to a system which can't
it's local IP stack (as in "can't ping the redundant default router").

Therefor in the case of not being able to ping, I would want the node to
be/become slave.
Is this possible?

I also have some doubts if drbd would successfully recover when both
nodes loose each other for a while (ending up in 
either Secondary/Unknown or Primary/Unknown)


> The problem is that with only an Ethernet communication line, 
> you have a single point of failure ( the IP Stack ).  If 
> something were to corrupt the IP stack on one machine (say, 
> the standby), then it wouldn't be able to communicate to the 
> master so it would take over.
> Having 2 totally different lines of communication (i.e. a 
> serial line ) you minimize that potential for problem because 
> even if Ethernet croaks, the serial line would still be alive 
> and communicating ( it would still see the master server ).
> If that isn't possible, you might want to have a dedicated 
> cross over Ethernet connection between the 2 servers.  That 
> can mitigate some problems ( of the switches failing ).  You 
> still need to deal with the single point of failure though ( 
> the IP stack ).
> Matt

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