[Linux-HA] 2 subnets separated by cisco 6509 switch
carson at taltos.org
Tue Mar 15 13:50:44 MST 2005
--On Tuesday, March 15, 2005 13:33:05 -0700 Alan Robertson <alanr at unix.sh>
> What heartbeat relies on is reliable communication between nodes. If you
> can have that, then you can be happy with it.
> Distance often makes that difficult.
> There are alternatives involving meatware stonith, but they're a bit more
This really is a solved problem, but it does require a quorum mechanism. It
should be practical to implement in heartbeat 2.x (now that it supports
more than 2 nodes). Of course with a quorum mechanism, somebody looses
badly in a site disaster with only 2 sites (one site or the other will have
the tie-breaking quorum member - if the majority site goes boom, human
intervention is required). But it does guarantee that split brain causes no
harm, and is no worse that the current STONITH failure case (data center
loss taking out server & STONITH device).
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