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

Kenneth Geisshirt kenneth at geisshirt.dk
Tue Mar 15 13:38:41 MST 2005

Alan Robertson wrote:
> 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 
>> and ?
> What heartbeat relies on is reliable communication between nodes.  If 
> you can have that, then you can be happy with it.

Also remember that IP addresses might migrate from one node to the 
other. This might be difficult if the nodes live in different subnets.

Cisco has some switches where you can configure VLAN across a WAN 
connection. These might be useful.


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