[Linux-HA] 2 subnets separated by cisco 6509 switch

Alan Robertson alanr at unix.sh
Tue Mar 15 13:33:05 MST 2005


ebay2 at readynote.com wrote:
> Wondering what constitutes disaster recovery exactly....
> 
> Considerations are ??? Number of switches between? Subnets?, Distance?
> Eg, Why peerd is considered Disaster-recovery while heartbeat isn't?

They consider themselves more of disaster recovery tools.  I'm not so 
convinced myself, by the way...

> I went the hearbeat route but I may have used disaster recovery.... We wanted 
> a Single IP address to adhere to...
> 
> Can I stretch HA to achieve disaster recovery for boxes separated by say 20km 
> across 1 cisco 6509 switch and 2 subnets, say 170.86.42.22 and 170.86.44.22 ?

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 
messy.





-- 
     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 Wilberforce



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